adapted from: Moss Flora of the Maritime Provinces. Robert R. Ireland. National Museum of Natural Sciences (Canada) & National Museums of Canada. (1982). Publications in botany. LINK
See Annotated Checklist of New England Mosses for range and habitat detail. Additional notes at bottom.
1 - Plants 3.5-4 cm; central stem leaves oblong; apices rounded-apiculate ... Alleniella complanata
1 - Plants to 2 cm; central stem leaves ovate to obovate; apices obtuse to broadly acute ... Alleniella besseri
1 - Leaves suborbicular to short-lingulate; synoicous (or dioicous); capsule cylindric, operculum conic to short-rostrate ... Aloina brevirostris
1 - Leaves ligulate; dioicous; capsule ovoid-cylindrical, operculum long-rostrate ... Aloina rigida
1 - Costa subpercurrent to percurrent ... Hygroamblystegium varium
1 - Costa ending near middle of leaf or somewhat above ... Amblystegium serpens
1 - Plants autoicous, often with sporophytes, perichaetial leaves sheathing; leaves glossy below, dull above, margins plane or recurved at base; papillae on leaf cells round or nearly so ... Amphidium lapponicum
1 - Plants dioicous, sporophytes rare but if present, perichaetial leaves not sheathing; leaves glossy, margins distinctly recurved from base to middle; papillae on leaf cells elliptic, often in rows and appearing as striae ... Amphidium mougeotii
1 - Leaves ovate to ovate-lanceolate, ecostate ... Andreaea rupestris
1 - Leaves narrowly lanceolate, costate -- 2
2 - Costa percurrent ... Andreaea rothii
2 - Costa subpercurrent ... Andreaea crassinervia
1 - Leaves with a long-filiform acumen; leaf margins revolute ... Claopodium rostratum
1 - Leaves apiculate, acute or obtuse; leaf margins plane -- 2
2 - Plants usually with attenuate branches (especially noticeable when dry); branch leaves gradually narrowed to an acute apex, scarcely contorted when dry ... Pseudanomodon attenuatus
2 - Plants lacking attenuate branches; branch leaves obtuse or apiculate, strongly contorted when dry -- 3
3 - Plants small, branches up to 5 cm long; branch leaves 2 mm long or less, auriculate at base, basal cells fimbriate-papillose on margins of auricles ... Anomodon rugelii
3 - Plants large, branches up to 10 cm long; branch leaves often over 2 mm long, without auricles at base, basal cells crenulate-papillose on margins ... Anomodon viticulosus
Anomodon minor (similar to A. viticulosus, see BFNA); Anomodon tristis keys directly.
1 - Median and upper leaf cells averaging 9-17 µm in longest dimension; leaves narrow, those near the middle of the stem less than 1 mm wide, often with 6 or more lamellae covering 1/3 of leaf near middle; dioicous ... Atrichum angustatum
1 - Median and upper leaf cells averaging 17 µm or more in longest dimension; leaves broad, those near the middle of the stem usually more than 1 mm wide with 0-6 (rarely up to 8) lamellae commonly covering less than 1/3 of leaf; monoicous or dioicous -- 2
2 - Median leaf cells thin-walled, noncollenchymatous or sometimes slightly so, often more than 30 x 24 µm; teeth few or lacking on dorsal surface of leaf lamina; dioicous -- 3
2 - Median leaf cells often thick-walled and strongly collenchymatous, rarely reaching 30 x 24 µm; teeth numerous on dorsal surface of lamina; monoicous or dioicous -- 4
3 - Median leaf cells averaging more than 20 µm in shortest dimension; cuticle of marginal leaf cells covered with minute verrucose or striate papillae; lamellae low, 1-4 cells high, sometimes lacking ... Atrichum crispum
3 - Median leaf cells averaging less than 20 µm in shortest dimension; marginal leaf cells smooth; lamellae high, 2-6 cells, always present ... Atrichum tenellum
4 - Lamellae averaging 4-6 cells high (up to 9 cells high) on mature upper leaves; plants autoicous with antheridia in inflorescence below archegonia; capsules straight or subarcuate and erect to inclined ... Atrichum altecristatum
4 - Lamellae lower, averaging 2-4 cells high (up to 8 cells high); autoicous or dioicous -- 5
5 - Plants dioicous, stems commonly over 3 cm high, densely clothed with whitish rhizoids, leaves dense; capsules often over 5 mm long, erect or inclined, subarcuate; common in wet habitats ... Atrichum crispulum
5 - Plants monoicous (at least some individuals), stems seldom over 3 cm high and not noticeably clothed with whitish rhizoids, leaves distant; capsules (excluding operculum) rarely reaching 5 mm long, inclined to horizontal, strongly arcuate; common in dry habitats ... Atrichum undulatum
1 - Leaves broadly oblong to ovate, coarsely serrate above; autoicous ... Aulacomnium heterostichum
1 - Leaves lanceolate to oblong-lanceolate, entire to serrulate; dioicous -- 2
2 - Small plants bearing pseudopodia with round clusters of fusiform gemmae only at the apices; often in dry habitats ... Aulacomnium androgynum
2 - Medium-sized to robust plants bearing pseudopodia with ecostate, leaf-like gemmae clustered at the apices and sparsely scattered below; usually in bogs or other wet habitats ... Aulacomnium palustre
Aulacomnium turgidum (rare alpine species often in pure cushions and having broad cucullate leaf apices and closely imbricate leaves, see BFNA).
1 - Leaves lanceolate, gradually tapering from the base to an acute apex; median leaf cells thick-walled, 1-2 papillae per cell ... Geheebia fallax
1 - Leaves lingulate with an obtuse to broadly acute apex, sometimes ending in a mucro; median leaf cells thin-walled, multipapillose -- 2
2 - Leaf margins plane or recurved at base; costae subpercurrent to percurrent; inner perichaetial leaves convolute, sheathing base of seta; setae yellow ... Streblotrichum convolutum
2 - Leaf margins recurved to middle of leaf or above; costae excurrent as a mucro; inner perichaetial leaves scarcely differentiated; setae red ... Barbula unguiculata
Aloina rigida keys directly; B. unguiculata f. apiculata is not a recognized form.
1 - Stems to 1-5 cm; leaves usually 4-5 mm, bases sheathing; capsules 1.0 mm; rare, montane ... Bartramia ithyphylla
1 - Stems to 0.5-8 cm; leaves 4-7 mm, bases laxly or scarcely sheathing; capsules 1.5-2.5 mm ... Bartramia pomiformis
1 - Costae extending 3/4 or more the leaf length -- 2
1 - Costae extending 1/2-2/3 the leaf length -- 3
2 - Leaves mostly 1 mm long or more, stem leaves shortly decurrent, margins entire to serrulate; median leaf cells long, 5-10:1; setae papillose above, smooth below, sometimes smooth throughout ... Sciuro-hypnum populeum
2 - Leaves mostly less than 1 mm long, stem leaves long-decurrent, margins serrulate to serrate; median leaf cells short, 3-5:1; setae papillose throughout ... Sciuro-hypnum reflexum
3 - Leaf margins entire to serrulate -- 4
3 - Leaf margins serrate to serrulate -- 6
4 - Plants dioicous; leaf margins usually plane above ... Brachythecium albicans
4 - Plants autoicous; leaf margins often recurved to near apices -- 5
5 - Plants large and turgid, leaves straight, often 3 mm long ... Brachythecium turgidum
5 - Plants not large and turgid, leaves often falcate, seldom reaching 3 mm long ... Brachythecium campestre (in part)
6 - Leaves smooth -- 7
6 - Leaves plicate -- 11
7 - Alar regions with numerous enlarged cells, often abruptly inflated and rounded; setae papillose throughout -- 8
7 - Alar regions with few, gradually enlarged cells, quadrate to rectangular, never abruptly inflated; setae papillose throughout or sometimes smooth below -- 10
8 - Stem leaves long-decurrent, alar cells round, abruptly inflated; often on boulders in and beside streams ... Brachythecium rivulare (in part)
8 - Stem leaves shortly decurrent or nondecurrent, alar cells quadrate to rectangular, not abruptly inflated; seldom near streams but often in drier habitats in lowland woods -- 9
9 - Stem leaves nondecurrent or nearly so, ovate, apices seldom twisted ... Brachythecium rutabulum (in part)
9 - Stem leaves shortly decurrent, often deltoid, apices twisted ... Sciuro-hypnum starkei
10 - Leaves falcate, often falcate-secund; setae papillose throughout; on soil or wood in moist to dry lowland woods ... Brachytheciastrum velutinum
10 - Leaves straight or nearly so; setae papillose above, smooth below; on soil or rocks near streams ... Sciuro-hypnum plumosum
11 - Stem leaves long-decurrent, alar cells round, abruptly inflated ... Sciuro-hypnum plumosum (in part)
11 - Stem leaves shortly decurrent or nondecurrent, alar cells quadrate to rectangular, not abruptly inflated -- 12
12 - Leaves strongly falcate, often falcate-secund -- 13
12 - Leaves straight to somewhat falcate -- 14
13 - Leaves on some stems and branches strongly crisped and curled; setae smooth ... Brachythecium erythrorrhizon
13 - Leaves never crisped or curled; setae often papillose ... Brachythecium campestre (in part)
14 - Plants dioicous -- 15
14 - Plants autoicous -- 16
15 - Stems small, usually less than 1 mm wide, leaves closely imbricate; capsules straight or slightly arcuate, erect ... Brachythecium acuminatum
15 - Stems large, mostly 1 mm wide or more, leaves loosely imbricate; capsules arcuate, inclined ... Brachythecium laetum (in part)
16 - Setae papillose (at least above) -- 17
16 - Setae smooth -- 18
17 - Leaves strongly plicate; setae papillose above, sometimes smooth below ... Brachythecium campestre (in part)
17 - Leaves weakly plicate or some smooth; setae papillose throughout ... Brachythecium rutabulum (in part)
18 - Plants with filiform leaf apices ... Brachythecium campestre (in part)
18 - Plants with acute to acuminate leaf apices that are rarely filiform -- 19
19 - Leaves often over 1.5 mm long, apices acuminate ... Brachythecium salebrosum
19 - Leaves 1,5 mm long or less, apices mostly acute ... Brachythecium laetum (in part)
B.acutum, B.capillaceum, B.falcatum, Sciuro-hypnum curtum not in MFMP.
1 - Branch leaves broad, 2-3: 1 , acute to broadly acuminate, twisted V2 turn at apex; upper leaf cells weakly prorate on dorsal surface ... Brachythecium novae-angliae
1 - Branch leaves narrow, 3-5:1, narrowly acuminate, not or only somewhat twisted at apex; upper leaf cells strongly prorate on dorsal surface ... Koponeniella graminicolor
1 - Costae ending below apex to percurrent -- 2
1 - Costae percurrent to excurrent -- 8
2 - Plants silvery-white (due to absence of chlorophyll in cells) ... Bryum argenteum
2 - Plants green, often with yellow, brown or red pigmentation -- 3
3 - Leaves obtuse to subacute -- 4
3 - Leaves acute -- 6
4 - Leaf margins recurved ... Bryum muehlenbeckii
4 - Leaf margins plane -- 5
5 - Plants small, usually less than 1 cm high, sterile stems julaceous; sporophytes often present, red, capsules nearly as broad as long; 1 or more bulbils sometimes occurring in leaf axils ... Bryum blindii
5 - Plants large, mostly 1 cm or more high, with distant, spreading leaves; clusters of septate, filiform gemmae present in leaf axils ... Bryum cyclophyllum
6 - Leaves nondecurrent or sometimes shortly decurrent; clusters of brown, filiform, septate, papillose gemmae often present in leaf axils ... Bryum capillare
6 - Leaves long-decurrent -- 7
7 - Leaf margins strongly recurved nearly to apex, unistratose ... Bryum pseudotriquetrum
7 - Leaf margins plane or somewhat recurved near base, sometimes bistratose ... Bryum weigelii
8 - Plants monoicous -- 9
8 - Plants dioicous -- 14
9 - Plants synoicous -- 11
9 - Plants autoicous -- 10
10 - Leaves with a bistratose border of linear cells; capsules clavate or clavate-cylindric, unsymmetric ... Bryum uliginosum
10 - Leaves with a unistratose border of linear cells; capsules elongate-ovate, symmetric ... Bryum pallescens
11 - Inner peristome teeth with appendiculate cilia ... Bryum creberrimum
11 - Inner peristome teeth with rudimentary cilia -- 12
12 - Leaves with a short, abruptly recurved apex; maritime plants ... Bryum salinum
12 - Leaves with a long, straight apex; plants seldom maritime -- 13
13 - Capsules short, averaging less than 3 mm long; inner peristome teeth not attached to outer teeth ... Bryum inclinatum
13 - Capsules long, averaging about 4-5 mm long; inner peristome teeth partially attached to outer teeth ... Bryum algovicum
14 - Plants lacking gemmae on rhizoids ... Bryum caespiticium
14 - Plants with globose to ovoid gemmae on rhizoids -- 15
15 - Gemmae yellow to orange ... Bryum tenuisetum
15 - Gemmae brown, red or violet -- 16
16 - Gemmae small, usually under 140 µm in diameter ... Bryum violaceum
16 - Gemmae large, usually over 140 µm in diameter ... Bryum subapiculatum
Bryum alpinum, amblydon, bimum, dichotomum, elegans, gemmiparum, klinggraeffii, laevifilium, lochocaulon, mildeanum, pallens, subapiculatum, veronse not in MFMP.
BFNA split some of Bryum into Gemmabryum, Imbribryum, Ptychostomum, & Rosulabryum. Try the BFNA Bryaceae key ... and good luck!
1 - Capsules clearly longer than broad, cylindric and not flattened dorsally ... Buxbaumia minakatae
1 - Capsules nearly as broad as long, dorsally flattened, especially when dry ... Buxbaumia aphylla
1 - Leaves appressed, close throughout the stems; costae short, reaching 3/4 the length of the leaves ... Warnstorfia straminea
1 - Leaves spreading, close only at apices of stems and branches; costae long, subpercurrent to percurrent -- 2
2 - Plants with numerous branches, often pinnate; stem leaves broad, sometimes nearly as broad as long, alar cells abruptly inflated; dioicous ... Calliergon giganteum
2 - Plants irregularly branched with few branches; stem leaves narrow, clearly longer than broad, alar cells gradually enlarged; autoicous ... Calliergon cordifolium
Calliergon richardsonii (rare northern species, see BFNA).
1 - Costae strong, single, reaching the middle of the leaves or beyond -- 2
1 - Costae weak, double or lacking, rarely single but if so, ending far below middle of the leaves -- 5
2 - Plants with squarrose or falcate-secund leaves ... Campylium chrysophyllum
2 - Plants with erect- to wide-spreading leaves -- 4
3 - Stem leaves lanceolate to ovate-lanceolate, gradually acuminate, alar cells enlarged and inflated ... Drepanocladus polygamus
3 - Stem leaves cordate-ovate, abruptly acuminate, alar cells not inflated but gradually enlarged ... Pseudocampylium radicale
4 - Plants large, leaves often 2 mm or more long; alar cells abruptly enlarged or inflated; pseudoparaphyllia lacking ... Campylium stellatum
4 - Plants small, leaves seldom reaching 1.5 mm long; alar cells not abruptly enlarged or inflated; pseudoparaphyllia present but rare -- 6
5 - Plants yellowish brown or brownish green; leaves crowded, bases imbricate, margins entire or serrate at apices, serrulate near recurved bases ... Campylophyllum halleri
5 - Plants green or yellowish green, rarely yellowish brown; leaves distant, bases rarely touching, margins serrulate to serrate near plane or rarely recurved bases ... Campylophyllopsis hispidula
Campylium protensum (segregate of C.stellatum that is smaller and creeping, see BFNA).
Campylophyllopsis sommerfeltii (segregate of C.hispidula with longer setae & smaller alar region, see BFNA Campylophyllum).
Campylophyllum montanum (similar to C.halleri but subalpine & semi-aquatic on acid rock, see Maine Mosses 2014).
1 - Median cells of branch leaves often more than 6:1; stem leaves abruptly apiculate; plants common ... Climacium dendroides
1 - Median cells of branch leaves usually 3-5:1, seldom reaching 7:1; stem leaves gradually acuminate; plants rare ... Climacium americanum
1 - Stem leaves plicate, strongly falcate-secund; alar cells weakly differentiated; leaf cells prorate on dorsal surface, the median long and narrow, 6-15:1; paraphylia numerous ... Cratoneuron falcatum
1 - Stem leaves smooth, straight or somewhat falcate-secund; alar cells strongly differentiated; leaf cells smooth, the median short and broad, 3-8:1; paraphyllia few ... Cratoneuron filicinum
1 - Capsules strumose, slightly curved; perigonial leaves acute or nearly so ... Cynodontium strumiferum
1 - Capsules not strumose, straight; perigonial leaves broadly obtuse ... Cnestrum alpestre
Cynodontium polycarpon (rare or mis ID; see BFNA discussion).
Cynodontium tenellum (rare alpine; see BFNA discussion under Cynodontium alpestre).
1 - Leaves obtuse or ending in an apiculus, upper cells papillose; peristome present ... Tortula obtusifolia
1 - Leaves acute to acuminate, upper cells smooth or papillose; peristome present or lacking -- 2
2 - Leaves with smooth cells, the margins bordered in lower half by a band of 1-5 rows of yellowish, thick-walled, linear cells; capsules inclined to horizontal, arcuate ... Tortula cernua
2 - Leaves with papillose cells, the papillae sometimes sparse or lacking on border cells which are yellowish, thick-walled, square to rectangular; capsules erect, straight ... Hennediella heimii
Tortula porteri (distinguished from T.obtusifolia by the more acute leaves with plane margins, see BFNA). See Tortula below for additional segregates.
1 - Medial stem leaves 0.7-1.4 mm wide; capsules exserted; endostome trellis perfect. ... Dichelyma falcatum
1 - Medial stem leaves 0.4-0.8 mm wide; capsules immersed or laterally emergent; endostome trellis imperfect -- 2
2 - Leaves narrow, linear-lanceolate, filiform-acuminate, costae long-excurrent ... Dichelyma capillaceum
2 - Leaves broad, lanceolate, acute to obtuse, costae subpercurrent to percurrent ... Dichelyma pallescens
1 - Leaves squarrose from an enlarged, clasping base -- 2
1 - Leaves not squarrose and lacking enlarged, clasping base -- 5
2 - Leaves strongly decurrent, apex broad, often obtuse; costae occupying 1/15-1/20 of base ... Diobelonella palustris (in part)
2 - Leaves not or weakly decurrent, apex narrow, usually acute; costae occupying 1/6-1/10 of leaf base -- 3
3 - Leaves entire to serrulate near apex; costae smooth; capsules ribbed orfurrowed -- 4
3 - Leaves serrate to serrulate to middle; costae dorsally toothed; capsules smooth ... Aongstroemia schreberiana
4 - Leaves strongly squarrose; capsules slightly strumose ... Aongstroemia schreberiana (in part)
4 - Leaves weakly squarrose; capsules not strumose ... Dicranellopsis subulata (in part)
5 - Leaves broad, apex obtuse, base decurrent ... Diobelonella palustris (in part)
5 - Leaves narrow, apex acute, base nondecurrent -- 6
6 - Capsules strumose, inclined, often nearly as broad as long ... Dicranella cerviculata
6 - Capsules not strumose, erect or inclined, usually much longer than broad -- 7
7 - Capsules strongly contracted under a portion of mouth making the mouth oblique ... Dicranella heteromalla
7 - Capsules not contracted under only a portion of mouth but sometimes contracted all around mouth -- 8
8 - Capsules erect ... Ruficaulis rufescens
8 - Capsules inclined -- 9
9 - Capsules smooth when dry and empty ... Calcidicranella varia
9 - Capsules ribbed or furrowed when dry and empty ... Dicranellopsis subulata (in part)
1 - Plants with most leaf apices broken off; usually sterile, occurring on wood, rarely on rock ... Dicranum viride
1 - Plants with most leaf apices present, rarely with a few apices broken; often fruiting, occurring on wood and various other substrates -- 2
2 - Leaf cells in upper one-third of leaf mostly quadrate, short-rectangular or rounded, usually less than 2:1, the walls with few or no pits -- 3
2 - Leaf cells in upper one-third of leaf mostly elongate, usually more than 2:1, the walls with many pits -- 11
3 - Plants with 1-6 terete flagella in some of the upper leaf axils ... Dicranum flagellare
3 - Plants lacking axillary flagella -- 4
4 - Leaves often undulate or rugose, especially near the apex -- 5
4 - Leaves not undulate or rugose -- 8
5 - Costae ending below apex to percurrent; leaf apices broadly acute; setae solitary -- 6
5 - Costae percurrent to excurrent; leaf apices narrowly acute; setae solitary to aggregate -- 7
6 - Leaves ovate to ovate-lanceolate; leaf cells strongly papillose above ... Dicranum spurium
6 - Leaves lanceolate to oblong-lanceolate; leaf cells smooth to weakly papillose above ... Dicranum undulatum
7 - Leaf cells commonly spinulose or strongly papillose; setae often aggregate ... Dicranum ontariense
7 - Leaf cells smooth or weakly papillose; setae solitary ... Dicranum condensatum (in part)
8 - Leaf laminae entirely bistratose above or with a few unistratose regions ... Dicranum fulvum
8 - Leaf laminae unistratose or with some bistratose regions on or near the margins -- 9
9 - Leaves small, usually less than 5.0 mm long and 0.5 mm wide ... Dicranum montanum
9 - Leaves large, usually 5-10 mm long and 0.5-1.0 mm wide -- 10
10 - Upper leaf margins commonly with bistratose regions; capsules usually ± strumose ... Dicranum fuscescens
10 - Upper leaf margins unistratose; capsules not strumose ... Dicranum condensatum (in part)
11 - Costae with a double row of guide cells (best observed at base of leaf); leaves 10-15 mm long; setae often aggregate ... Dicranum majus
11 - Costae with one row of guide cells; leaves often less than 10 mm long; setae solitary or aggregate -- 12
12 - Leaves undulate -- 13
12 - Leaves not undulate -- 14
13 - Stems densely matted with a whitish or reddish-brown tomentum; leaves strongly toothed; setae usually aggregate ... Dicranum polysetum
13 - Stems without or with little tomentum; leaves weakly toothed; setae solitary or rarely two per perichaetium ... Dicranum bonjeanii (in part)
14 - Costae lacking dorsal ridges ... Dicranum leioneuron
14 - Costae with 2-4 dorsal ridges -- 15
15 - Leaves weakly toothed, usually broadly acute ... Dicranum bonjeanii (in part)
15 - Leaves strongly toothed, narrowly acute ... Dicranum scoparium
Dicranum acutifolium (subalpine-alpine similar to D.fuscescens see BFNA).
Dicranum elongatum (subalpine-alpine, plants are relatively small, slender, glossy, in dense, compact tufts; leaves are short, narrow, usually less than 6 × 0.5 mm, ending in a long, fine, tubulose subula; see BFNA).
Dicranum muehlenbeckii (rare, see Discussion in BFNA).
1 - Distichium capillaceum ... Distichium capillaceum
1 - Capsule ovoid, horizontal; spores 30-47 µm ... Distichium inclinatum
1 - Plants often over 1 cm high; dioicous, seldom with sporophytes; occurring on soil over and in crevices of boulders and cliffs ... Flexitrichum flexicaule
1 - Plants seldom reaching 1 cm high; autoicous or dioicous, frequently with sporophytes; occurring on soil along trails, roads, and in clearings -- 2
2 - Leaves short, 1-3 mm, often imbricate; plants dioicous; capsules erect, cylindric; setae red to brown when mature -- 3
2 - Leaves long, 3-5 mm, spreading; plants autoicous; capsules erect to inclined, ovoid; setae yellow or red when mature -- 4
3 - Leaves imbricate, apices obtuse, margins plane or nearly so; perichaetial leaves with abruptly narrowed apex shorter than sheathing base; tubers lacking on rhizoids ... Ditrichum lineare
3 - Leaves not imbricate, apices acute, margins recurved; perichaetial leaves with narrowed apex equal to or longer than sheathing base; tubers present ... Ditrichum pusillum
4 - Setae yellow; peristome teeth mostly less than 0.5 mm long; spores papillose, 16-25 µm ... Ditrichum pallidum
4 - Setae orange to red; peristome teeth long, more than 0.5 mm long, often up to 1 mm; spores reticulate, 10-14 µm ... Ditrichum rhynchostegium
Ditrichum tortuloides (rare segregate of D.ambiguum see BFNA).
Originally the hook mosses characterized by a long single costa and strongly falcate to circinate leaves. 9 additional species could key to this group.
1 - Leaves entire -- 2
1 - Leaves serrulate to serrate -- 4
2 - Alar cells inflated ... Drepanocladus aduncus
2 - Alar cells not inflated -- 3
3 - Plants green; leaf cells with thin, nonpitted walls; stems lacking a central strand, epidermal cells not enlarged, thick-walled ... Hamatocaulis vernicosus
3 - Plants red to black, sometimes green; basal leaf cells with thick, pitted walls; stems with a central strand, epidermal cells enlarged, thin-walled ... Scorpidium revolvens
4 - Leaves plicate, alar cells quadrate, not inflated; stem epidermal cells enlarged, thin-walled ... Sanionia uncinata
4 - Leaves smooth, alar cells round to oblong, inflated; stem epidermal cells not enlarged, thick-walled -- 5
5 - Costae extending 3/4 or more the length of the leaves; inflated basal cells of leaves extending from margins to costa; dioicous ... Warnstorfia exannulatas
5 - Costae extending to middle of leaves, rarely beyond; inflated basal cells of leaves usually not extending to costa; autoicous ... Warnstorfia fluitans
1 - Plants small, stems seldom reaching 1 cm high, lacking gemmae; leaves often apiculate, costae smooth on dorsal surface; sporophytes frequently present, capsules smooth when dry ... Encalypta ciliata
1 - Plants large, stems often 1 cm high or more, gemmae usually present; leaves obtuse to broadly acute, costae papillose on dorsal surface; sporophytes not known from the Maritimes, capsules spirally ribbed when dry ... Encalypta procera
Encalypta rhaptocarpa (Leaves oblong-lanceolate, excurrent with a distinct awn; Peristome present, weak; Calyptra base erose; Capsules red and strongly ribbed; Rare northern calciophile; see BFNA).
1 - Setae yellow; leaves slender acuminate; rare ... Entodon brevisetus
1 - Plants with small leaves, seldom reaching 1.5 mm long; not aquatic but often growing in moist habitats -- 2
2 - Branches julaceous; leaves abruptly acute to apiculate; margins weakly serrulate distally ... Entodon seductrix
2 - Branches somewhat complanate; leaves gradually acute; margins serrulate and often notched distally ... Entodon cladorrhizans
1 - Plants with large leaves, 1.5 mm long or more; aquatic, occurring on rocks in or beside streams ... Rhynchostegium aquaticum
1 - Plants with small leaves, seldom reaching 1.5 mm long; not aquatic but often growing in moist habitats -- 2
2 - Plants somewhat complanate; leaves acute to acuminate, often with twisted apices; setae rough ... Oxyrrhynchium hians
2 - Plants often julaceous or nearly so; leaves acute to obtuse, apices not twisted; setae smooth ... Eurhynchiastrum pulchellum
1 - Leaves wholly or partly bordered with narrow, elongated cells ... Fissidens bryoides
1 - Leaves lacking border of elongated cells -- 2
2 - Leaves irregularly serrate near apex, often bordered with a band of lighter colored cells -- 3
2 - Leaves finely and evenly crenulate, sometimes serrulate near apex, not bordered with a band of lighter cells -- 4
3 - Leaf cells averaging 12 µm or more in longest dimension; leaf lamina unistratose ... Fissidens adianthoides
3 - Leaf cells smaller, averaging less than 12 µm in longest dimension; leaf lamina with scattered patches of bistratose regions ... Fissidens dubius
4 - Costa ending 3-10 cells below apex; sporophyte arising from stem apex ... Fissidens osmundioides
4 - Costa ending 1-2 cells below apex or reaching apex, often excurrent as a short mucro or apiculus; sporophyte arising laterally from stem -- 5
5 - Costa excurrent; leaves apiculate, unistratose; plants autoicous ... Fissidens taxifolius
5 - Costa ending 1-2 cells below apex or percurrent; leaves mucronate, bistratose in patches; plants dioicous ... Fissidens bushii
See BFNA for the species below:
Fissidens closteri (rare on rocks in streams).
Fissidens exilis (persistent protonema and numerous capsules; distinguished from other tiny Fissidens by 2-3 rows of irregularly elongate intralaminal cells in the vaginant laminae).
Fissidens fontanus (aquatic of slow moving water; profusely branched, delicate, & feathery; leaves often 10X or more length:width).
Fissidens minutulus (calciophile similar to F.bryoides).
Fissidens subsibaliaris (costa obscured by chlorophyllose cells distally, short perichaetial branches in the axils of proximal leaves).
1 - Plants often yellowish to brownish green; leaves keeled -- 2
1 - Plants usually green; leaves plane or concave -- 3
2 - Leaves longer than broad, 2-3:1, seldom reaching 4 mm wide ... Fontinalis antipyretica
2 - Leaves about as broad as long, 1.0-1.5:1, often over 4 mm wide ... Fontinalis antipyretica var. gigantea
3 - Leaves plane -- 4
3 - Leaves concave -- 5
4 - Leaves obtuse to truncate, serrate at apices ... Fontinalis sullivantii (in part)
4 - Leaves acute, entire or serrulate at apices ... Fontinalis hypnoides
5 - Leaves rigid, appressed to slightly spreading ... Fontinalis dalecarlica
5 - Leaves flaccid, spreading, seldom appressed -- 6
6 - Leaf margins often involute ... Fontinalis novae-angliae
6 - Leaf margins not involute ... Fontinalis sullivantii (in part)
Fontinalis sphagnifolia (ecologically dimorphic, see BFNA)
1 - Leaves (mainly the upper ones) with a hyaline mucro or awn; capsules immersed or exserted -- 2
1 - Leaves lacking hyaline mucro or awn; capsules immersed -- 9
2 - Leaves with margins plane or involute -- 3
2 - Leaves with one or both margins recurved -- 4
3 - Leaves spreading to nearly squarrose; capsules exserted; peristome present ... Grimmia olneyi
3 - Leaves imbricate; capsules immersed; peristome lacking ... Grimmia anodon (in part)
4 - Upper leaves often obtuse, bearing clusters of gemmae at their tips ... Dryptodon anomalus
4 - Upper leaves acute to acuminate, lacking gemmae -- 5
5 - Leaves with a long awn, often 1/4 the length of the leaf or more -- 6
5 - Leaves with a mucro or short awn less than 1/4 the length of the leaf -- 8
6 - Lower leaf cells sinuose, the marginal cells at the leaf base with cross-walls thicker than the longitudinal walls; capsules exserted on prominent setae; peristome teeth present ... Grimmia longirostris
6 - Lower leaf cells not sinuose, or, if so, the walls all about the same thickness; capsules immersed and setae not evident; peristome teeth present or lacking -- 7
7 - Leaves mostly in definite rows; peristome teeth lacking ... Grimmia anodon (in part)
7 - Leaves not in definite rows; peristome teeth present ... Schistidium apocarpum (in part)
8 - Leaves papillose on dorsal surface of costa near apex ... Schistidium apocarpum (in part)
8 - Leaves smooth on dorsal surface of costa ... Schistidium rivulare (in part)
9 - Leaves ligulate to linear-lanceolate, rarely ovate-lanceolate, mostly obtuse, sometimes acute, entire or crenulate at apex -- 11
9 - Leaves ovate-lanceolate, acute or narrowly obtuse, serrate to serrulate at apex -- 10
10 - Leaves papillose on dorsal surface of costa near apex ... Schistidium apocarpum (in part)
10 - Leaves smooth on dorsal surface of costa ... Schistidium rivulare (in part)
11 - Leaf apex narrowly obtuse, sometimes acute, leaves not eroded; maritime plants growing on rocks in the spray zone ... Schistidium maritimum
11 - Leaf apex broadly obtuse, the leaves often eroded; plants not maritime, on rocks in or by streams ... Schistidium agassizii
G.donniana, G.incurva, G.laevigata, (Dryptodon) muehlenbeckii, G. pilifera, G.sessitana, G.unicolor, S.crassithecium, S.dupretii, S.lancifolium, S.liliputanum, S.trichodon, S.viride (not in MFMP).
1 - Leaf margins plane; upper leaf cells indistinct, averaging less than 12 µm in longest dimension; capsules light brown; opercula deciduous; spores 9-14 µm in longest dimension ... Gymnostomum aeruginosum
1 - Leaf margins recurved below on one or both sides; upper leaf cells clear, usually averaging more than 12 µm in longest dimension; capsules dark brown to reddish brown; opercula persistent, often remaining attached to the columella (systylius); spores 16-24 µm in longest dimension ... Hymenostylium recurvirostrum
G. recurvirostrum var. latifolium not recognized
1 - Stem leaves gradually long-acuminate; leaf margins entire to crenulate-serrate ... Haplocladium microphyllum
1 - Stem leaves abruptly short-acuminate; leaf margins irregularly serrate ... Haplocladium virginianum
1 - Stems with central strand absent; stems closely, evenly pinnate, branches nearly equal; leaf apices short-acuminate; setae 4-6 cm; capsules 3-4 mm; paraphyllia to 27 cells in length ... Helodium blandowii
1 - Stems with central strand present; stems loosely subpinnate, branches unequal; leaf apices long-acuminate; setae 2-2.8 cm; capsules 2-2.5 mm; paraphyllia 7-11 cells in length -- 2
2 - Leaves broadly cordate-ovate; apices abruptly acuminate; laminal cell walls thick, especially in margins, abaxial surface strongly 1-papillose centrally or nearer distal ends of lumen; leaf costa proximal abaxial surfaces with 1 or 2 scattered teeth ... Helodium elodioides
2 - Leaves ovate-lanceolate; apices gradually acuminate; laminal cell walls thin, especially in margins, abaxial surface smooth or weakly papillose-prorulose; leaf costa proximal abaxial surfaces smooth ... Helodium paludosum
1 - Leaves acute to obtuse, costae subpercurrent to percurrent ... Hygroamblystegium varium
1 - Leaves acuminate, costae excurrent in many leaves ... Cratoneuron filicinum
1 - Epidermal cells of the stems enlarged, thin-walled and hyaline ... Hygrohypnella ochracea
1 - Epidermal cells of the stems not enlarged, thick-walled-- 2
2 - Costae single or double, strong, often reaching to the middle of the leaves or beyond-- 3
2 - Costae double, weak, usually ending below the middle of the leaves, sometimes lacking-- 4
3 - Leaves often falcate-secund, small, seldom over 1.5 mm long and 0.5 mm wide, the bases not clasping the stems ... Hygrohypnum luridum
3 - Leaves not falcate-secund, large, often over 1.5 mm long and 0.5 mm wide, the bases clasping the stems ... Platyhypnum bestii
4 - Leaves ovate to suborbicular, about as broad as long ... Platyhypnum duriusculum
4 - Leaves lanceolate to ovate-lanceolate, longer than broad-- 5
5 - Leaves often squarrose, margins serrulate to serrate throughout ... Campylophyllum montanum
5 - Leaves not squarrose, margins entire or denticulate at apex ... Pseudohygrohypnum eugyrium
Hygrohypnum closteri (see BFNA).
Hageniella micans (usually keyed in this genus, on rock near streams; see BFNA).
Pseudohygrohypnum subeugyrium (see Discussion in BFNA).
1 - Stems regularly branched, commonly bipinnate to tripinnate ... Hylocomium splendens
1 - Stems irregularly branched, sometimes bipinnate but rarely tripinnate -- 2
2 - Leaves small, seldom reaching 2 mm in length; branch leaves usually less than 1 mm wide ... Hylocomium umbratum
2 - Leaves large, mostly 2 mm long; branch leaves usually more than 1 mm wide -- 3
3 - Stem leaves acute to short-acuminate; costae single, extending to middle of leaves ... Hylocomium pyrenaicum
3 - Stem leaves abruptly narrowed to a long acumen; costae double, rarely reaching middle of leaves ... Loeskeobryum brevirostre
1 - Epidermal cells of stems enlarged, thin-walled-- 2
1 - Epidermal cells of stems small, thick-walled-- 4
2 - Plants with numerous branches, usually regularly pinnate; leaves filiform-acuminate ... Pseudohygrohypnum fauriei
2 - Plants with few branches, never pinnate; leaves acute to broadly acuminate-- 3
3 - Alar cells abruptly enlarged and inflated; pseudoparaphyllia lacking ... Calliergonella lindbergii
3 - Alar cells gradually enlarged; pseudoparaphyllia foliose, broadly lanceolate ... Stereodon pratensis
4 - Alar regions indistinct, composed of only a few differentiated cells that are sometimes abruptly enlarged and inflated-- 8
4 - Alar regions distinct, composed of numerous, small, quadrate, short-rectangular, or round cells, usually about 8-12 on the margins and extending several rows inward-- 5
5 - Leaf margins serrulate to serrate throughout; pseudoparaphyllia broadly lanceolate, usually ending in one cell; autoicous ... Jochenia pallescens (in part)
5 - Leaf margins entire or serrulate above, entire below; pseudoparaphyllia deeply incised and ciliate or narrowly lanceolate, ending in a row of 3-6 cells; autoicous or dioicous-- 6
6 - Autoicous, often with sporophytes; pseudoparaphyllia deeply incised and ciliate ... Callicladium imponens (in part)
6 - Dioicous, seldom with sporophytes; pseudoparaphyllia filamentous to narrowly lanceolate, not incised-- 7
7 - Plants with broad stems and branches, often 0.7-1.5 mm wide; leaves usually secund ... Hypnum cupressiforme
7 - Plants with slender stems and branches, seldom over 0.5 mm wide; leaves erect-spreading, only slightly secund ... Hypnum cupressiforme var. filiforme
8 - Plants large, stems and branches often 1 mm wide or more; pseudoparaphyllia present, incised and ciliate, or lacking-- 9
8 - Plants small to medium-sized, stems and branches mostly less than 1 mm wide; pseudoparaphyllia or paraphyllia present, never incised and ciliate-- 10
9 - Alar regions with few differentiated cells, usually only 1-3 in marginal rows; pseudoparaphyllia lacking or when rarely present not incised and ciliate; capsules broad, horizontal, wrinkled when dry ... Calliergonella curvifolia
9 - Alar regions with several differentiated cells, usually more than 3 in marginal rows; pseudoparaphyllia present, incised and ciliate; capsules suberect, slender, smooth ... Callicladium imponens (in part)
10 - Pseudoparaphyllia present; capsules straight or nearly so; occurring on wood, usually bases of trees, rarely on acidic rock ... Jochenia pallescens (in part)
10 - Paraphyllia present; capsules arcuate; occurring on calcareous rock ... Drepanium fastigiatum
Hypnum andoi (resembles H. cupressiforme var. filiforme; rare, coastal; plants closely affixed to substrate; leaves long-attenuate; pseudoparaphyllia tipped by 1 elongate cell; alar cells are often brown and weakly excavate; see BFNA).
Hypnum jutlandicum (rare, coastal; plants yellowish green, glossy and pinnate; yellow stems; filiform pseudoparphyllia; see Discussion in BFNA).
Aquilonium plicatulum (rare, boreal; frequently close-pinnate stems, yellowish green to golden green leaves; green to yellow stems; stems with hyalodermis; auriculate leaves; 5-6 pigmented, thick-walled alar cells; see Hypnum plicatum in BFNA).
Roaldia revoluta (small plants, on enriched substrates; revolute leaf margins; remarkable alar region; see Hypnum revolutum in BFNA).
1 - Plants strongly complanate-foliate, epidermal cells of stems large and thin-walled; leaves often abruptly acuminate; dioicous ... Isopterygiopsis muelleriana
1 - Plants weakly complanate-foliate, epidermal cells of stems small and thick-walled; leaves usually gradually acuminate; autoicous or dioicous -- 2
2 - Pseudoparaphyllia present, filamentous; alar cells on margins usually quadrate or transversely elongate, often over 12 pm wide ... Isopterygium tenerum
2 - Pseudoparaphyllia lacking; alar cells on margins rectangular, seldom quadrate, usually less than 12 pm wide -- 3
3 - Leaves symmetric, the apical margins entire or rarely minutely serrulate; costae short or indistinct and often lacking; asexual reproductive bodies rarely present, 2-5 celled cylindric or fusiform brood bodies, small, less than 0.1 mm long; autoicous ... Isopterygiopsis pulchella
3 - Leaves sometimes asymmetric, the apical margins often serrulate to serrate; costae distinct, rarely lacking, often one branch extending l/3 lengthof leaves; asexual reproductive bodies common, large, usually more than 0.1 mm long -- 4
4 - Leaves mostly cultriform, seldom symmetric, often undulate; asexual reproductive bodies twisted-vermiform, with 1-5 teeth at apex, rarely any such structures below, commonly borne at or near apices of stems and branches; sex organs unknown ... Pseudotaxiphyllum distichaceum
4 - Leaves rarely cultriform, mostly symmetric, seldom undulate; asexual reproductive bodies resembling parent plants but smaller, bearing reduced leaves from apex to base of stems, borne throughout stems and branches except at apices; dioicous ... Pseudotaxiphyllum elegans
Pseudisothecium myosuroides keys directly.
1 - Capsule erect and symmetric; seta short, 3-6 mm ... Arctoa fulvella
1 - Capsule suberect to inclined; seta long, 7-16 mm -- 2
2 - Distal laminal cells elongate; capsules 1.3–2 mm distinctly ribbed when dry; leaves unistratose smooth or weakly papillose on dorsal surface, alar cells inflated, clearly differentiated from cells above ... Arctoa starkei
2 - Distal laminal cells short, rectangular or quadrate; capsule 0.8–1.2 mm smooth when dry -- 3
3 - Plants in vertical rock cracks in dense tufts; leaves falcate secund; distal laminal cells rectangular ... Kiaeria falcata
3 - Plants in loose tufts; leaves erect-spreading, flexuose; upper cells quadrate to short-rectangular, strongly papillose on dorsal surface, alar cells gradually grading into cells above ... Arctoa blyttii
1 - Plants in low, compact cushions or turfs; stems usually less than 1 cm; leaves 2-4(-6) mm, limb shorter than (rarely equal to) length of sheath ... Leucobryum albidum
1 - Plants in tall, compact cushions or turfs; stems mostly more than 2 cm; leaves mostly 3-9 mm, limb longer than (1.5-3) times length of sheath ... Leucobryum glaucum
1 - Secondary stems often bearing numerous flagelliform branchlets in leaf axils; leaves long-acuminate; sporophytes unknown ... Leucodon sciuroides
1 - Secondary stems lacking flagelliform branchlets; leaves acute to short-acuminate -- 2
2 - Leaves not plicate, not secund; apical laminal cells papillose abaxially; stems julaceous, short or rarely elongate ... Leucodon julaceus
2 - Leaves ± plicate, secund or rarely so; apical laminal cells smooth or rarely papillose abaxially; stems not julaceous, elongate ... Leucodon brachypus
1 - Stem and branch leaves differentiated, stem leaves longer than broad; apices ± obliquely acuminate and subsecund; branches somewhat curved at apices; capsules subcylindric, curved ... Leskea polycarpa
1 - Stem and branch leaves similar, not much longer than broad; apices not oblique or subsecund; branches not curved at apices; capsules oblong-cylindric, straight or slightly curved -- 2
2 - Branches ± tightly foliate; leaf apices acute or sometimes narrowly blunt; leaves ± 2-plicate; margins irregularly revolute proximally, especially when dry; endostome segments as long as exostome teeth; operculum ± pointed ... Leskea gracilescens
2 - Branches loosely foliate; leaf apices rounded-obtuse to sometimes acute or acuminate; leaves not plicate (stem leaves occasionally slightly plicate); margins not revolute; endostome segments less than 1/3 exostome teeth length; operculum blunt ... Leskea obscura
1 - Leaf margins lacking border of differentiated cells or border indistinct; leaf margins singly serrate or a few teeth in pairs ... Mnium stellare
1 - Leaf margins with border of linear cells; leaf margins doubly serrate -- 2
2 - Costae toothed on dorsal surface; plants dioicous or synoicous -- 3
2 - Costae smooth on dorsal surface; plants synoicous -- 5
3 - Leaves long and narrow, 4-6 times as long as wide; costae subpercurrent ... Mnium hornum
3 - Leaves short and broad, 2-4 times as long as wide; costae percurrent to excurrent -- 4
4 - Plants synoicous; costae with dorsal teeth lacking or with 1-2 poorly developed teeth ... Mnium marginatum (in part)
4 - Plants dioicous; costae with dorsal teeth strongly developed ... M. ambiguum
5 - Leaves scarcely reaching 1.5 mm wide; plants seldom with capsules; peristome teeth yellow to light brown ... Mnium marginatum (in part)
5 - Leaves often over 1.5 mm wide and up to 3 mm wide; plants usually with capsules; peristome teeth red to purplish brown ... Mnium spinulosum
Mnium lycopodioides (very similar to M.marginatum; see Discussion & last Mnium couplet BFNA).
Mnium thomsonii (morphologically variable; very similar to M.spinulosum; see BFNA).
1 - Plants green to yellow-brown; leaves not sheathing at the base, folded and sometimes crisped when dry; alar cells enlarged and pellucid; ; often on rock ... Oncophorus virens
1 - Plants light to very dark green; leaves sheathing at the base, strongly contorted when dry; alar cells not differentiated; usually on logs in wet sites ... Brideliella wahlenbergii
In the field, similar to Paraleucobryum, some Dicranums, D.scoparium in particular, Bartramia. Easily separated by strumose capsules or microscopically.
1 - Leaves broadly obtuse, margins plane; gemmae usually present ... Nyholmiella obtusifolia
1 - Leaves acute to narrowly obtuse, margins recurved; gemmae rarely present -- 2
2 - Capsules with superficial stomata (phaneropore) -- 3
2 - Capsules with immersed stomata (cryptopore) -- 5
3 - Capsules immersed to slightly exserted above perichaetial leaves, strongly contracted under mouth giving capsules bulbous appearance ... Lewinskya sordida
3 - Capsules exserted above perichaetial leaves, weakly or not at all contracted under mouth -- 4
4 - Capsules obscurely ribbed when dry and mature ... Lewinskya speciosa
4 - Capsules smooth or nearly so when dry and mature ... Lewinskya elegans
5 - Plants on calcareous rock -- 6
5 - Plants on trees; capsules immersed to slightly exserted above perichaetial leaves -- 7
6 - Capsules exserted; 1-stratose leaf margins ... Orthotrichum anomalum
6 - Capsules immersed or emergent; multistratose leaf margins ... Orthotrichum strangulatum
_ _ _ _(with 1-stratose, revolute margins ... Orthotrichum lescurii)
7 - Leaves wide-spreading to nearly squarrose; capsules strongly constricted below mouth when dry; exothecial cells of ribs in bands 5-8 cells wide ... Orthotrichum stellatum
7 - Leaves erect-spreading; capsules not or only slightly constricted below mouth when dry; exothecial cells of ribs in bands 4 cells wide ... Orthotrichum ohioense
Orthotrichum pumilum (distinguished by strongly ribbed capsules; reflexed peristome teeth; apiculate leaves with cells larger than 14 µm; papillae that are very small or absent - see BFNA).
Orthotrichum pusillum (distinguished by smooth, oblong capsules sharply contracted to the seta; 16 exostome teeth erect or recurved when old; some leaves having 1-4 small denticulations at the apex; see BFNA).
1 - Leaves lanceolate, margins singly serrate, upper cells papillose at upper ends ... Philonotis marchica
1 - Leaves ovate-lanceolate, margins singly or doubly serrate (adjacent ends of marginal cells forming a pair of projections), upper cells papillose at lower ends, sometimes at upper or both ends -- 2
2 - Leaf apices twisted and turned to one side when dry ... Philonotis americana
2 - Leaf apices straight or twisted but, if twisted, not turned to one side when dry -- 3
3 - Costae percurrent to short-excurrent ... Philonotis fontana
3 - Costae long-excurrent ... Philonotis tomentella
Philonotis yezoana (On cliffs & steep banks, wet or dry; Dark green color; Centrally papillose laminal cells; see BFNA).
1 - Setae short, capsules immersed in perichaetial leaves ... Physcomitrium immersum
1 - Setae long, capsules exserted above perichaetial leaves -- 2
2 - Empty capsules shallow, often with a wide, flared mouth; exothecial cells sometimes collenchymatous; spores less than 40 µm in longest dimension ... Physcomitrium collenchymatum
2 - Empty capsules turbinate, not shallow or with a flared mouth; exothecial cells not collenchymatous; spores often more than 40 µm in longest dimension ... Physcomitrium pyriforme
Physcomitrium serratum (Globose capsule lacking obvious line of dehiscence; Exothecial cells collenchymatous; Spores spiculose-papillose; see Aphanorrhegma in BFNA).
1 - Leaves obovate, margins toothed to middle, rarely below -- 2
1 - Leaves ± elliptic, margins toothed to base or nearly so -- 3
2 - Leaves dark green, dull, cells irregularly rounded to hexagonal, small, 25 µm or less in longest dimension; setae solitary ... Plagiomnium cuspidatum
2 - Leaves light green, shiny, cells hexagonal, large, mostly over 25 µm in longest dimension; setae 1-3 ... Plagiomnium drummondii
3 - Median leaf cells large, often over 50 µm in longest dimension; synoicous; setae 1-5 ... Plagiomnium medium
3 - Median leaf cells small, mostly less than 50 µm in longest dimension; dioicous or rarely synoicous; setae solitary, rarely 2-4 -- 4
4 - Teeth on leaf margins often composed of 3 or more cells; dioicous; setae solitary; operculum conic to apiculate ... Plagiomnium ciliare
4 - Teeth on leaf margins composed of 1-2 cells; synoicous; setae 1-4; operculum long-rostrate ... Plagiomnium rostratum
Plagiomnium ellipticum (Similar to P.ciliare; Morphologically variable; Leaf apices rounded, bases not decurrent; Median leaf cells over 50 µm; Teeth composed of 1 cell; see BFNA).
1 - Leaves with broadly recurved margins; decurrent portion of leaves often auriculate, rounded at the ends, composed of many inflated, spherical cells in 2-8 vertical rows; capsules striate or wrinkled when dry ... Plagiothecium denticulatum
1 - Leaves with plane or narrowly recurved margins; decurrent portion of leaves never auriculate, tapering to pointed ends, composed of mostly rectangular cells in 1-5 vertical rows; capsules smooth or sometimes striate or wrinkled when dry -- 2
2 - Plants small, leaves erect-spreading, mostly 1 mm or less long; dioicous; rare, on bases of trees, rotten wood and fern tussocks in wet lowlands ... Plagiothecium latebricola
2 - Plants larger, leaves mostly more than 1.5 mm long; autoicous or dioicous; common at low or high altitudes on various substrata -- 3
3 - Median cells of leaves 10 µm wide or less; plants usually complanate-foliate, often with undulate, flat, asymmetric leaves without recurved apices or sometimes leaves smooth, secund with apices pointing toward substratum; autoicous ... Plagiothecium laetum
3 - Median cells of leaves often over 10 µm wide; plants usually julaceous, sometimes somewhat complanate, with symmetric, concave leaves with apices often recurved; dioicous ... Plagiothecium cavifolium
1 - Mature leaves with a distinct single costa; leaf margins entire or nearly so; alar regions with ± 10 quadrate or transversely rectangular cells on margins; plants autoicous; capsules erect to inclined, straight to slightly arcuate; propagula lacking; occurring on wood ... Pseudoamblystegium subtile
1 - Mature leaves lacking costa or costa scarcely distinct; leaf margins usually minutely serrulate; alar regions with 0-10 quadrate or rarely transversely rectangular cells on margins; plants autoicous or dioicous; propagula sometimes present; occurring on rock or humus over rock -- 2
2 - Propagula sometimes present; plants dioicous; capsules erect and straight ... Platydictya jungermannioides
2 - Propagula lacking; plants autoicous; capsules cernuous and arcuate ... Serpoleskea confervoides
Serpoleskea minutissima (Ecostate; On rock; Leaf margins entire at insertion, serrulate elsewhere; Perichaetial leaf margins coarsely dentate distally; Capsules inclined, horizontal, or sometimes suberect; see Platydictya key in BFNA for an alternate key to this entire diminutive group).
1 - Perichaetial leaf lamina in transverse section uniformly 1-stratose at shoulder; plants autoicous, antheridia enclosed in leafy buds in axils of stem leaves ... Pleuridium subulatum
1 - Perichaetial leaf lamina in transverse section at least partly 2-stratose at shoulder; plants paroicous, antheridia in axils of stem leaves naked or subtended by a membranous brac -- 2
2 - Shoulders of perichaetial leaves with jagged teeth; leaf lamina in transverse section 2-stratose on either side of costa, 1-stratose towards margin, plicate at the transitional area ... Pleuridium ravenelii
2 - Shoulders of perichaetial leaves uniformly serrulate but never jagged; leaf lamina in transverse section sporadically to completely 2-stratose leaving the margin narrow and 1-stratose, concave, plicae absent ... Pleuridium acuminatum
1 - Plants scattered over persistent green protonema, gametophyte leaves small, less than 8 mm high; lamellae few, 10-15 ... Pogonatum pensilvanicum
1 - Gametophytes large, 2-20 cm high; lamellae numerous, 25-60 -- 2
2 - Plants with stems usually over 4 cm high; capsules over 3 mm long, stomata present ... Polytrichastrum alpinum
2 - Plants with stems less than 4 cm high; capsules 3 mm long or less, stomata absent -- 3
3 - Stems mostly simple; marginal cells of lamellae flat-topped in cross-section, the lumen usually broader than long ... Pogonatum dentatum
3 - Stems often branched; marginal cells of lamellae rounded in cross-section, the lumen usually longer than broad ... Pogonatum urnigerum
Polytrichastrum septentrionale (Recent promotion of an alpine Polytrichastrum alpinum variety; Plants small (1-2 cm); Leaves entire to finely and remotely serrate toward the tip; Capsules ovoid to subglobose; Leaves not fragile, not constricted at junction of sheath and blade, blade persistent; See Polytrichastrum key in BFNA).
1 - Plants with gemmae in leaf axils -- 2
1 - Plants lacking gemmae -- 6
2 - Gemmae scarce, one per axil, round or obovoid bodies -- 3
2 - Gemmae numerous, 2-several per leaf axil, linear, round or obovoid bodies -- 4
3 - Gemmae red when mature ... Pohlia andalusica
3 - Gemmae yellow or green when mature ... Pohlia bulbifera (in part)
4 - Gemmae round or obovoid, 2-3 per leaf axil, lacking points at apex ... Pohlia bulbifera (in part)
4 - Gemmae linear, often more than 3 per leaf axil, with points at apex -- 5
5 - Gemmae with a single point or sometimes 2-3 points at apex ... Pohlia proligera
5 - Gemmae with 2-4 points at apex ... Pohlia annotina
6 - Plants julaceous, leaves strongly concave, imbricate ... Anomobryum julaceum
6 - Plants not julaceous, leaves flat to weakly concave, spreading -- 7
7 - Capsules about as wide as long -- 8
7 - Capsules decidedly longer than wide -- 9
8 - Plants green or yellow; capsules with superficial stomata ... Pohlia lescuriana
8 - Plants whitish green; capsules with immersed stomata ... Pohlia wahlenbergii
9 - Capsules long and slender, about 6-8 times as long as wide, with a neck of equal or greater length than rest of capsule ... Pohlia elongata
9 - Capsules short and broad, about 3-5 times as long as wide, with a neck much shorter than rest of capsule -- 10
10 - Plants whitish green and shiny; laminal cells linear-vermicular ... Pohlia cruda
10 - Plants yellowish green to dark green and dull; laminal cells hexagonal to rhomboidal ... Pohlia nutans
Not in MFMP: drummondii (with gemmae), longicolla (similar to P.cruda), melanodon (similar to P.wahlenbergii), obtusifolia (sub alpine-alpine snow melt areas); see BFNA Pohlia key.
1 - Leaf margins folded over upper surface of leaf, entire except at apex -- 2
1 - Leaf margins plane when wet, serrate from apex to leaf sheath -- 4
2 - Leaves ending abruptly in a long, hyaline awn ... Polytrichum piliferum
2 - Leaves ending gradually in a short, reddish brown awn -- 3
3 - Stems long, often over 5 cm high, commonly matted with whitish rhizoids; plants of bogs ... Polytrichum strictum
3 - Stems short, seldom up to 5 cm, rhizoids scarcely noticeable; plants of dry habitats ... Polytrichum juniperinum
4 - Marginal cells of lamellae flat-topped or notched in crosssection, often thick-walled -- 5
4 - Marginal cells of lamellae rounded in cross-section, all the lamellae walls the same thickness -- 7
5 - Stems large, often over 5 cm high; many marginal cells of lamellae strongly notched in cross-section, walls not or little thicker than other lamellae cells; capsules about as long as wide -- 6
5 - Stems small, rarely up to 5 cm; marginal cells of lamellae not or weakly notched in cross-section, the walls noticeably thicker than other lamellae cells; capsules longer than wide ... Polytrichum ohioense
6 - Inner perichaetial leaves not or just exceeding upper leaves ... Polytrichum commune
6 - Inner perichaetial leaves extending 1-2 mm above upper leaves; plants mostly of relatively dry habitats ... Polytrichum perigoniale
7 - Lamellae numerous, covering most of the leaf except for 2-8 cells along the margins; capsules mostly over 4 mm long; plants of moderately dry habitats ... Polytrichum formosum
7 - Lamellae few, often covering only 1/3-1/2 of leaf, rarely extending to within 5-10 cells of the margins; capsules mostly less than 4 mm long; plants of fens and other wet habitats ... Polytrichum longisetum
Polytrichum pallidisetum (In spruce-fir forests; Capsule 4 angled, lacks enlarged apophysis; Pale yellowish seta; see Discussion of Polytrichastrum pallidisetum in BFNA).
Polytrichum densifolium (Promotion of a P.formosum variety; see Polytrichastrum key in BFNA).
1 - Margins of leaves noticeably serrulate throughout, rarely entire; transversely rectangular or quadrate alar cells commonly in a few rows, most leaves with less than 10 on margins and less than 30 in entire alar region; spores averaging more than 19 µm in longest dimension ... Pylaisia intricata
1 - Margins of leaves entire or serrulate above; transversely rectangular or quadrate alar cells in several rows, many leaves with more than 10 on margins and about 50-60 in entire alar region; spores averaging 19 µm or less in longest dimension -- 2
2 - Leaves straight and erect, some rarely falcate-secund ... Pylaisia polyantha
2 - Leaves falcate-secund, especially at stem and branch tips and when dry ... Pylaisia selwynii
1 - Leaves with a hyaline apex of varying length -- 2
1 - Leaves lacking hyaline apex -- 8
2 - Cells of hyaline apex smooth or serrulate to toothed -- 3
2 - Cells of hyaline apex multipapillose -- 6
3 - Leaf margins often bistratose near apex -- 4
3 - Leaf margins unistratose -- 5
4 - Stems usually with many, short, lateral branches ... Racomitrium affine (in part)
4 - Stems lacking short, lateral branches or rarely a few present ... Racomitrium sudeticum
5 - Cells just below hyaline apex mostly isodiametric ... Racomitrium heterostichum
5 - Cells just below hyaline apex mostly elongate ... Racomitrium microcarpon
6 - Margins of hyaline apex erose; plants grayish green ... Racomitrium lanuginosum
6 - Margins of hyaline apex not erose; plants yellowish green -- 7
7 - Stems with few, short, lateral branches, irregularly arranged along stem; leaf papillae often over 6 µm in height (measured in cross-section near leaf middle) ... Racomitrium canescens
7 - Stems with many, short, lateral branches at regular intervals along stem; leaf papillae seldom reaching 6 µm in height ... Racomitrium ericoides
8 - Apical leaf cells elongate; laminae unistratose ... Racomitrium fasciculare
8 - Apical leaf cells isodiametric or nearly so; laminae unistratose or bistratose -- 9
9 - Leaf apices broad, crenulate to dentate; laminae unistratose ... Racomitrium aciculare
9 - Leaf apices narrow, entire or nearly so; laminae bistratose on margins near apex ... Racomitrium affine (in part)
Racomitrium aduncoides (separated from R.aciculare by a spurred costa extending no more than 3/4 of the leaf; see Codriphorus aduncoides in BFNA).
Racomitrium venustum (separated from R.affine by leaf margins that are 2-stratose for 1-3 cells rows; see Bucklandiella venusta in BFNA).
1 - Leaves small, 3-6 mm long; costae subpercurrent; rhizoids restricted to leaf axils in lower part of stem ... Rhizomnium punctatum
1 - Leaves large, 5-11 mm long; costae often percurrent; rhizoids scattered along lower part of stems -- 2
2 - Border cells of leaf bases quadrate to short-rectangular, often bearing rhizoids; leaf cells large, averaging 90 µm or more in longest dimension ... Rhizomnium appalachianum
2 - Border cells of leaf bases rectangular, lacking rhizoids; leaf cells smaller, averaging less than 90 µm in longest dimension ... Rhizomnium magnifolium
Rhizomnium pseudopunctatum (similar to R.magnifolium but synoicous; see BFNA).
1 - Leaves plicate; alar cells not or slightly differentiated -- 2
1 - Leaves not plicate; alar cells differentiated; (costa to 1/3 leaf length) -- 3
2 - Costae 1/2-2/3 leaf length; medial laminal cells coarsely prorate; stem leaf apices gradually narrowed, acumina broad, flat (occasionally rugose) ... Rhytidiadelphus triquetrus
2 - Costae less than 1/4 leaf length; medial laminal cells smooth; stem leaf apices abruptly narrowed, acumina slender, channeled ... Rhytidiadelphus loreus
3 - Stem leaves not crowded (stem visible between leaves) except at stem apices, erect-spreading to squarrose; bases not or scarcely sheathing; leaves broadly ovate-triangular; stems irregularly branched to pinnate; moist, usually shaded sites ... Rhytidiadelphus subpinnatus
3 - Stem leaves crowded (stem concealed by leaves), strongly squarrose-recurved; bases subsheathing; leaves ovate; stems remotely branched to irregularly pinnate; well-drained, open to partially shaded sites, near coast or in grassy, disturbed habitats ... Rhytidiadelphus squarrosus
key adpated from BNFA
_ _ _ _See BFNA for alternate key
1 - Leaves with acute apices -- 2
1 - Leaves with obtuse apices -- 3
2 - Leaf margins serrulate to base or nearly so; costae subpercurrent to percurrent, not filling apices; setae straight when wet ... Seligeria brevifolia
2 - Leaf margins entire; costae excurrent, filling apices; setae arcuate when wet ... Blindiadelphus recurvatus (in part)
3 - Leaf apices broadly obtuse; setae straight when wet ... Blindiadelphus diversifolius
3 - Leaf apices narrowly obtuse; setae arcuate when wet -- 4
4 - Costae subpercurrent to percurrent, not filling apices ... Blindiadelphus campylopodus
4 - Costae excurrent, filling apices ... Blindiadelphus recurvatus (in part)
Seligeria calcarea (similar to S.donniana but with entire leaves; capsules gradually contract to seta though a shriveled neck; well-developed peristome; length of the capsule > width).
Seligeria donniana (tiny, stiff plants with stoutly subulate leaves with serrulate proximal portions; capsules hemispheric, relatively small, lack a peristome).
Seligeria tristichoides (somewhat 3 ranked; subulate leaves with costa filling apex; turbinate capsules; persistent columella; well-developed peristome).
1 - Leaves small, usually less than 1.5 mm long; apical leaf cells 3-5:1 ... Sematophyllum demissum
1 - Leaves large, often 1.5 mm long or more; apical leaf cells 4-8:1 ... Sematophyllum marylandicum
1 - Leaf margins toothed with large, multicellular teeth; hypophysis turbinate, pink to light purple, wrinkled when dry ... Splachnum ampullaceum
1 - Leaf margins toothed with small, unicellular teeth, sometimes entire; hypophysis campanulate, yellow, dark red or purple, smooth when dry -- 2
2 - Leaf margins toothed nearly to base; hypophysis dark red to purple ... Splachnum rubrum
2 - Leaf margins toothed only to middle of leaf; hypophysis yellow ... Splachnum luteum
Splachnum pensylvanicum (Setae shorter than 1 cm; hypophysis greenish, dark red or purplish distally, globose or narrowly pyriform, as wide or slightly wider than urn; leaves long lanceolate; apices slenderly long-acuminate; see BFNA).
1 - Setae straight or somewhat bent, smooth ... Tetraphis pellucida
1 - Setae sharply bent in the middle, strongly papillose above bend ... Tetraphis geniculata
1 - Protonematal flaps narrow, linear, acute, to 2.5 mm, usually entire; stem leaves acuminate, sharply pointed ... Tetrodontium brownianum
1 - Protonematal flaps ovate-lingulate, less than 0.5 mm, dentate, with a large acute apical cell; stem leaves obtuse ... Tetrodontium ovatum
1 - Stem leaf laminal cell papillae simple ... Thelia hirtella
1 - Stem leaf laminal cell papillae usually 3-6-branched -- 2
2 - Stems creeping, densely and regularly 1-pinnate, often densely tomentose, branches simple; leaf acumina usually spreading-piliferous ... Thelia asprella
2 - Stems often ascending, sparsely and irregularly branched, lightly tomentose, branches irregularly branched; leaf acumina erect, apiculate ... Thelia lescurii
1 - Plants small, mostly less than 3 cm long and 1 cm wide; leaf cells multipapillose; autoicous -- 2
1 - Plants large, mostly over 3 cm long and 1 cm wide; leaf cells unipapillose; dioicous -- 3
2 - Branch leaves incurved-catenulate when dry; paraphyllia simple ... Pelekium minutulum
2 - Branch leaves imbricate when dry; paraphyllia often branched ... Rauiella scita
3 - Plants 1-pinnate ... Abietinella abietina
3 - Plants 2-3 pinnate -- 4
4 - Stem leaves arched and standing out from stem when dry; papillae on paraphyllia at ends of cells ... Thuidium recognitum
4 - Stem leaves appressed to slightly spreading when dry; papillae on paraphyllia near the middle of the cells-- 5
5 - Stem leaves acute to acuminate, rarely filiform-acuminate; inner perichaetial leaves with long cilia ... Thuidium delicatulum
5 - Stem leaves with a hyaline, filiform-acumination, composed of 3-8 cells; inner perichaetial leaves without cilia or with only a few short ones ... Thuidium assimile
Pelekium pygmaeum (Papillose stems and branches; see BFNA).
1 - Leaves falcate-secund, often twisted distally, widest just beyond base; rhizoid initials restricted to stem leaf proximal costa surface; usually in Sphagnum-dominated sites ... Tomentypnum falcifolium
1 - Leaves straight, not or little twisted distally, widest at base; rhizoids initials on stem leaf proximal abaxial costa surface and on stems just below leaf insertion; rich fens ... Tomentypnum nitens
1 - Leaf apices deciduous ... Tortella fragilis
_ _ _ _(Tortella nidita var fragifolia will also key here. See BFNA Tortella tortuosa var. fragilifolia discussion for differentiation.)
1 - Leaf apices present, not deciduous -- 2
2 - Leaves gradually narrowing from the base to a slenderly acute apex; dioicous ... Tortella tortuosa
2 - Leaves obtuse to obtusely acute with a mucronate apex; autoicous ... Tortella humilis
Tortella densa (rare (ME) alpine segregate of T.tortuosa; see BFNA under T.tortuosa var. arctica).
Tortella arctica (rare (VT) segregate of T.inclinata; see BFNA under T.inclinata var. densa).
1 - Leaf apices ending in a long, sharply toothed awn; leaf cells multipapillose ... Syntrichia ruralis
1 - Leaf apices acute or mucronate, entire or serrulate; leaf cells smooth or unipapillose -- 2
2 - Leaf margins inrolled; globose or ellipsoidal gemmae on upper surface of costae; occurring on tree trunks ... Syntrichia papillosa
2 - Leaf margins recurved; propagula lacking; occurring on soil and rocks ... Tortula mucronifolia
Syntrichia montana (Rare, subalpine; see BFNA)
Tortula truncata (Leaves awned, obovate to spatulate; Cells smooth; see BFNA)
Tortula (Pottia) truncata keys directly; Tortula acaulon keys directly as Phascum cuspidatum
1 - Capsule neck about the length of the urn ... Trematodon ambiguus
1 - Capsule neck about 2–3 times the length of urn ... Trematodon longicollis
1 - Gemma present at leaf tips; upper leaves with stout excurrent costa; on rocks or trees near coast associated with salt spray. ... Plenogemma phyllantha
1 - Gemmae absent; leaves with nearly percurrent costa-- 2
2 - Plants on acidic rocks -- 3
2 - Plants on trees -- 4
3 - Leaves flexuose when dry; rare northern species ... Ulota curvifolia
3 - Leaves erect-appressed, not crisped or contorted when dry; common ... Ulota hutchinsiae
4 - Capsules pyriform, with a small, puckered mouth when dry ... Ulota coarctata
4 - Capsules not pyriform, not or only slightly puckered below mouth when dry, ribs separated by more or less broad furrows in the upper half of urn-- 5
5 - Empty capsules with ± straight furrows; endostome slender and fragile; leaves markedly crisped when dry, abruptly narrowing from a concave base ... Ulota intermedia
5 - Empty capsules with sinuous or irregular furrows; endostome robust and ± persistent ; leaves slightly or moderately crisped when dry, gradually narrowing from a plane to slightly concave base ... Ulota crispula
Distinguishing the last 2 species is relatively easy with experience though it hardly seems worth the effort for such widespread and common species. They can also be separated as below with mature intact capsules:
A - Total sporophyte length 1.8-4.0 mm; endostome segments incurved when dry, uniseriate with thickened and prominent transverse walls; all the cells of the exothecial bands hyaline with pale yellow thickened lateral walls ... Ulota intermedia
A - Total sporophyte length 3.0-6.0 mm; endostome segments incurved, erect or patent when dry, uniseriate or irregularly biseriate with thin transverse walls; cells of the exothecial bands evenly pale yellow, at least in the two central rows ... Ulota crispula
1 - Capsule cleistocarpous; operculum not differentiated, peristome absent, seta less than 0.05 cm, cladautoicous; Leaves long-lanceolate, leaf mucro commonly strong, Laminal margins erect or almost plane ... Weissia muehlenbergiana
1 - Capsule stegocarpous, operculum falling -- 2
2 - Capsules narrowed at mouth, smooth, peristome lacking; Laminal margins erect or almost plane, occasionally very broadly incurved; mucro strong and often cylindric ... Weissia brachycarpa
2 - Capsules not or scarcely narrowed at mouth, usually plicate, peristome present, often short and rudimentar;y Laminal margins distally strongly and usually sharply incurved or inrolled; mucro variable ... Weissia controversa
1 - Gemmae fusiform, 5-7 celled ... Zygodon conoideus
1 - Gemmae clavate, 3-5 celled -- 2
1 - Gemmae with longitudinal septa; leaves oblong-lanceolate to lanceolate ... Zygodon viridissimus
1 - Gemmae absent longitudinal septa ; leaves linear- to elongate-lanceolate ... Zygodon rupestris
• Adapted from: Moss Flora of the Maritime Provinces. Robert R. Ireland. National Museum of Natural Sciences (Canada) & National Museums of Canada. (1982). Publications in botany. LINK. Some couplets are adapted from BFNA.
• Genera are listed in alphabetical order. They are not grouped by family. As many of the species and genera have changed, many of these groupings are designated sensu lato which indicates the nomenclature has changed. Newer names have been substituted as appropriate. The page number is the page the genus occurs in Ireland's original text.
• Nomenclature per: William R. Buck and Bernard Goffinet "A new checklist of the mosses of the continental United States and Canada," The Bryologist, 127(4), 484-549, (11 December 2024). https://doi.org/10.1639/0007-2745-127.4.484.
• Species in the new checklist above but that are not in Ireland are in red text and included in several ways. If the new species is a simple nomenclatural change, the new name has been substituted. If the new species could easily be added to the key, that has been done often with adaptations from BFNA. If the new species is a segregate of an existing species, a line has been added below the parent species with distiguishing features. If the new species was not added to the key, it is listed with or without notes below the genus key.
• BFNA refers to the Bryophyte sections of Flora of North America. Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.
• Synonyms for the Bryophyte Flora of North America are not presently indicated but my Flora of North America Moss Synonyms page may be helpful. My Annotated Checklist of New England Mosses includes synonyms for Ireland and all of the recent field guides for New England as well as many from BFNA. Both lists are easily searchable by using the 'find' or 'find in/on page' feature of your browser.
• BFNA is available online and thus referenced throughout this key. 'Maine Mosses' (two volumes) by Bruce Allen has superb species notes and is always worth consulting! It is available from the New York Botanical Gardens shop.
Errors or improvements? Email Jeff at info@DigitalNaturalist.info.
last update 2025-Aug-13