A Perspective Oriented Guide for the Identification of North American Moss Genera

Sub-Guide to Rarely Branched (mostly acrocarpous) Mosses

Revised through 23 July 2012

Reminder - A dagger () indicates that not all of the species within the given genus have the character(s) defining that Group. Abbreviations for the distribution of taxa are found at the end of the Concordance. Abbreviations for the number of stereid bands in costa cross sections are found in the Introduction and at the end of this page.


Group A1 - Shoots flat or angular, not round (Skeleton)

Shoots flattened; leaves 2-ranked (lying in one plane).

Leaves distichous (attached in two rows on opposite sides of the stem).

Leaves cleft at anterior edge and clasping posterior edge of next leaf; WS

Fissidens

Leaves conduplicate, crowded, and progressively larger; the "Sword " moss; WS*

Bryoxiphium

Leaves flat, decurrent and confluent; protonemata luminous; "Goblin Gold"; WS*

Schistostega

Leaves needle-like; a roughened subula from a sheathing, shiny-white base; WS

Distichium

Leaves complanate (attached all around the stem, but twisted into one plane).

Leaves with a long, single costa; cells smooth.

Leaves distant on stoloniferous shoots and bordered by linear cells; WS

Plagiomnium

Leaves crowded, unbordered and +undulate; capsules plicate (dry); E

Aulacomnium

Leaves ecostate; cells short and pleuripapillose; GC

Erpodium

Shoots triangular ; leaves 3-ranked .

Plants minute with immersed capsules; leaves broadly ovate with recurved apiculi; WS

Acaulon

Plants larger with exserted capsules; leaves ovate lanceolate, squarrose and decurrent.

Cells strongly papillose; plants on dry soils; CA

Triquetrella

Cells smooth; in calcareous wetlands.

Capsules with well-defined neck; endostome longer than exostome; N

Meesia

Capsules short & black (golf clubs); endostome reduced to lacking; N

Catoscopium

Shoots angular ; leaves 4-5 ranked .

Stems densely tomentose; leaves squarrose recurved; in calcareous wetlands; N

Paludella

Stems smooth; leaves crowded and appressed; on soil near rocks; A/A

Conostomum

Group A2 - Shoots julaceous when wet (Skeleton)

Stems red

Stems freely forked; plants whitish; capsule necks extremely long; A/A

Plagiobryum

Stems sparsely forked; capsule necks mostly short to moderate in length.

Cells long (~ 8:1); N*

Anomobryum

Cells intermediate (~4:1).

Upper leaves abruptly acuminate; capsules erect; peristome single; NW

Aongstroemia

Upper leaves apiculate; capsules pendent; peristome double; WS

Bryum

Stems green

Cells unipapillose and +stellate; leaves concave-cucullate; A/A.

Aulacomnium

Cells +prorulose; leaves 5-ranked and serrate; plants bluish-white; A/A

Conostomum

Cells smooth; leaves radially arranged.

Leaves serrulate and unbordered; immersed capsules: E

Pleuridium

Leaves entire and bordered with longer cells; exserted capsules; WS

Bryum

Group A3 - Stems distinctly tomentose (Skeleton)

Stems covered with pigmented (reddish to brownish) rhizoidal tomentum to near apex.

Leaves squarrose-recurved and heart shaped; fens; N

Paludella

Leaves ovate to broadly elliptical.

Rhizoidal initials in longitudinal rows; endostome fused into a dome; N

Cinclidium

Rhizoidal initials not in rows; endostome segments free; N*

Rhizomnium

Leaves oblong- lanceolate to oblong-lingulate.

Cells pleuripapillose; terminal cell long and smooth; brood bodies axillary; N*

Zygodon

Cells unipapillose; terminal cell papillose; brood bodies terminal; WS

Aulacomnium

Cells smooth; leaves broadly lingulate; a copper -sulfur moss; WS (E)

Scopelophila

Leaves narrowly lanceolate from an ovate, plicate base; WC, NW

Anacolia

Leaves lanceolate to subulate -setaceous; WS

Dicranum

Stems covered with white-wooly tomentum.

Leaves with green sheets (lamellae) on their surface; bogs; N*

Polytrichum

Leaves lacking lamellae; WS

Dicranum

Group A4 - Stems red (Skeleton)

Plants julaceous .

Stems freely forked; leaves with distinct, +reflexed point ; cells in oblique rows; A/A

Plagiobryum

Stems occasionally forked; leaves ovate to ovate-lanceolate and concave.

Leaves broadly obtuse to acute; costa ending subpercurrent; cells ~8:1; N*

Anomobryum

Leaves abruptly acuminate; costa percurrent; cells ~4:1; NW

Aongstroemia

Leaves obtuse to acute; costa percurrent to excurrent; cells ~4:1; WS

Bryum

Plants with stems covered with pigmented (reddish to brownish) tomentum .

Leaf cells >3:1; WS

Bryum

Leaf cells <2:1.

Rhizoidal initials in longitudinal rows; endostome fused into a dome; N

Cinclidium

Rhizoidal initials not in rows; endostome segments free; N*

Rhizomnium

Plants neither julaceous nor tomentose.

Leaves bordered by elongated cells.

Leaves distinctly toothed.

Cells strongly bulging; AK

Trachycystis

Cells smooth.

Cells very large (to 150x50); leaves rugose; WC, NW, CO

Roellia

Cells smaller (up to 50); leaves plane; WS

Mnium

Leaves entire.

Leaves +dimorphic (+distichous lateral leaves and smaller dorsal leaves); WC

Epipterygium

Leaves of one kind; WS

Bryum

Leaves not bordered.

Leaves serrulate +throughout; cells prorulose; WS

Philonotis

Leaves +serrulate near the apex; cells smooth.

Leaves subulate; alar cells inflated, thick-walled and reddish; N*

Blindia

Leaves not subulate; alar cells +undifferentiated; WS

Pohlia

Group A5 - Leaves squarrose-recurved (Skeleton)

Leaves squarrose-recurved when dry (or wet).

Leaves 5-ranked and folded to appear heart shaped; stems densely tomentose; fens; N

Paludella

Leaves squarrose-recurved only when wet (+appressed when dry).

Leaves 3-ranked, long-decurrent and with papillose-crenulate margins; CA

Triquetrella

Leaves subulate -setaceous from a sheathing base; disturbed soil; N

Trichodon

Leaves with wavy margins; hyaline basal and marginal cells; on dry limestone; SE

Pleurochaete

Leaves distinctly toothed in upper half; cells papillose.

Leaf lamina +bistratose; stem hyalodermis present; peristome lacking; SW

Rhexophyllum

Leaf lamina unistratose; stem hyalodermis lacking; peristome present; SE

Leptodontium

Leaves lacking the above unique characteristics.

Cell walls irregularly thickened; cell lumens stellate; A/A

Didymodon

Cell walls of uniform width; cell lumens +rounded.

Cells intermediate in length; WS

Dicranella

Cells short.

Leaves +bordered by longer, or shorter and thick -walled cells; 1*; WS

Tortula

Leaves unbordered; 2* ; WS

Barbula

A6 - Leaves falcate-secund (Skeleton)

Plants blackish; leaves multistratose; capsules valvate ; on rocks; NW

Andreaeobryum

Plants grayish; costa >1/2 leaf breadth with 3(4) cell layers; green striations on dorsal surface of leaves; N*

Paraleucobryum

Plants green; leaves unistratose and lacking striations; costa usually <1/5 leaf breadth.

Alar cells clearly differentiated; plants large , mostly >1cm.

Alar cells pigmented; capsules rarely strumose; various habitats; 2*; WS

Dicranum

Alar cells pale; capsules strumose ; on alpine rocks; 0*; A/A

Kiaeria

Alar cells +undifferentiated; plants small, mostly <1cm; WS

Dicranella

Group A7 - Leaves subulate / setaceous (8:1 or greater) (Skeleton)

Plants small to minute (mostly <5 mm high) with +immersed capsules growing on bare soil, usually as winter annuals ; the "pygmy ephemerals " as defined here.

Setae curved ; capsules laterally emergent and operculate; FL and GA

Eccremidium

Setae straight ; capsules immersed and cleistocarpous.

Capsules pyriform with a conspicuous, stomatose neck; spores small; WS

Bruchia

Capsules globose to ovoid , lacking a distinct neck.

Calyptrae mitrate or cucullate; spores numerous and small; WS

Pleuridium

Calyptrae rudimentary; spores few and large (>100); E

Archidium

Plants larger with exserted capsules growing on various substrates.

Leaves squarrose - recurved (wet); subula roughened throughout by cell ends; N

Trichodon

Leaves with bases distinctly incurved to expanded and clasping.

Cells intermediate in length and prorulose/papillose; upper cells + bistratose; WS

Bartramia

Cells intermediate in length and smooth.

Capsules with distinct , very long necks; WS

Trematodon

Capsules lacking a distinct neck.

Plants minute; peristome double with entire, papillose teeth; NT

Pseudoditrichum

Plants larger ; peristome single with forked teeth.

Teeth divided to base, round and papillose; WS

Ditrichum

Teeth divided to mid - point , flat and pitted - striolate ; WS

Dicranella

Cells short and smooth.

Upper cells + bistratose; capsules inclined, asymmetric and strumose; WS

Oncophorus

Upper cells unistratose; capsules erect , symmetric and cylindrical; SW

Symblepharis

Leaves with a broad , single costa (>1/3 the leaf width).

Alar cells inflated and hyaline or colored (brownish to reddish).

Costa 3(4) cell layers thick (middle layer green; external layers hyaline); N*

Paraleucobryum

Costa lacking the above unique characters.

Inner basal cells pale, enlarged and extending up along the costa; N*

Dicranodontium

Inner basal cells little differentiated; WS

Campylopus

Alar cells +undifferentiated.

Costa of 3(4) cell layers (middle layer green; external layers hyaline); E

Brothera

Costa lacking the above unique characters; reddish, axillary hairs common; WS

Leptobryum

Leaves lacking the above unique characteristics.

Alar cells distinctly differentiated .

Capsules curved and strumose (goiter-like swellings); on rocks; A/A

Kiaeria

Capsules obovoid to pyriform; on rocks .

Capsules ribbed (dry); peristome teeth wide-flaring, +split and striolate; N

Arctoa

Capsules smooth (dry); peristome teeth erect, +entire and papillose; N*

Blindia

Capsules lacking any of the above unique characters; substrates various .

Cells with cuticular ridges; peristome teeth +entire and papillose; N*

Dicranoweisia

Cells smooth; peristome teeth forked and pitted-striolate below; WS

Dicranum

Alar cells + undifferentiated.

Stems tomentose & red; leaves serrate above & recurved below; WC, NW

Anacolia

Stems tomentose at base; leaf margins doubly serrate; archegonia +basal; CP

Pyrrhobryum

Stems lacking tomemtum & green.

Cells intermediate to long; peristome teeth usually present.

Plants small (<2mm); leaves little altered (dry); on rocks; WS

Seligeria

Plants larger (>5mm); leaves twisted (dry); on wood; SA, WC

Orthodontium

Cells short ; annulus compound; peristome teeth mere stubs; WS*

Brachydontium

Group A8 - Leaves dimorphic (Skeleton)

Leaves costate , 4-ranked and bordered ; dorsal leaves smaller; stems red ; cells smooth; WC

Epipterygium

Leaves ecostate , 4-ranked and complanate ; ventral leaves smaller; cells pleuripapillose; GC

Erpodium

Group A9 - Leaves with hair-points or awns (Skeleton)

Plants minute (mostly <5 mm high) with +immersed capsules growing on bare soil ,
usually as winter annuals ; the "pygmy ephemerals " as defined here.

Leaves with lamellae on the upper end of the costa; WS

Pterygoneurum

Leaves with filaments on the upper end of the costa.

Leaves "fleshy " with inrolled margins; filaments on very broad costa; WC

Aloina

Leaves thin with reflexed to revolute margins; filaments on narrow costa; W

Crossidium

Leaves lacking lamellae or filaments

Leaves with a revolute margin; cells pleuripapillose; WS

Phascum

Leaves with reflexed tips; cells with single blunt papillae; WS*

Acaulon

Leaves with plane margins and tips; cells smooth.

Capsules exserted and peristomate; calyptrae cucullate; NW

Stegonia

Capsules +emergent and operculate; calyptrae persistent, 4-angled and split; E

Pyramidula

Capsules immersed and cleistocarpous; spores few and large (>100); TX

Lorentziella

Plants growing on dung , animal remains, or other highly nitrogenous materials; the "dung mosses ".

Hypophysis greatly differentiated and colored; peristome teeth chambered; N, CP, SA

Splachnum

Hypophysis narrowly pyriform and +urn-colored; peristome teeth not chambered; N

Tetraplodon

Hypophysis lacking; cleistocarpous; A/A

Voitia

Plants lacking any of the above unique characteristics.

Leaves "fleshy" from crowded lamellae covering a very broad costa; WS

Polytrichum

Leaves with a broad (1/3 - 1/2 leaf width) single costa; WS

Campylopus

Leaves ecostate.

Cells +isodiametric throughout with conspicuous primordial utricles; TX

Erpodium

Cells short rhomboidal (>3:1) above; TX, OK

Venturiella

Leaves with distinct border.

Cells short (+isodiametric); pleuripapillose or smooth; WS

Desmatodon

Cells intermediate in length; smooth.

Capsules pendent and pyriform; WS

Bryum

Capsules erect and +cylindric; GC, SW, SA

Brachymenium

Leaves with large, lax and hyaline basal cells contrasting with dense upper cells.

Basal cells pale with brown, thickened cross walls; calyptrae campanulate; WS

Encalypta

Basal cells thin -walled and non-pigmented throughout; calyptrae cucullate.

Peristome of 32 twisted teeth on a high basal membrane; WS

Tortula

Peristome of 32 +erect teeth on a low basal membrane; WS

Desmatodon

Leaves lacking the above unique characteristics.

Leaf cells distinctly papillose; marginal cells greener ; on mountain rocks and soil; WC, SW

Pseudocrossidium

Leaf cells smooth or indistinctly ornamented.

Plants in tufts on tree trunks and branches (rarely on rocks); diplolepideous.

Leaves crisped when dry; basal cells yellow, thick -walled and in diagonal rows; WC

Ulota

Leaves not crisped when dry; basal cells undifferentiated; WS*

Orthotrichum

Plants in tufts, cushions and mats on rocks; haplolepideous.

Calyptrae large, campanulate, plicate and lacerate at base.

Leaves ovate to obovate; WS (W)

Jaffueliobryum

Leaves ovate-lanceolate and biplicate; N*

Coscinodon

Calyptrae small, cucullate or mitrate.

Capsules systylious; calyptrae short; in wetter habitats; WS

Schistidium

Capsules not systylious; calyptrae reaching operculum; in dryer habitats; WS

Grimmia

Plants on soil primarily.

Cells intermediate in length; capsules pendent and pyriform; WS

Bryum

Cells short (+isodiametric); capsules mostly erect and cylindrical; WS

Desmatodon

Group A10 - Leaves with lamellae, ridges, or filaments (Skeleton)

Leaves with green , sheet-like lamellae .

Leaves with a very broad costa covered by >20 lamellae.

Leaves mostly bistratose; caducous awns ; peristome lacking; A/A

Lyellia

Leaves mostly unistratose; peristome present.

Lamellar apical cells papillose; capsules +terete.

Leaves subtubulose; lamellar apical cells elliptic-pyriform; WS

Polytrichastrum

Leaves oblong lanceolate; lamellar apical cells +rounded; WS

Pogonatum

Lamellar apical cells smooth or ridged; capsules sharply 4-5 angled; WS

Polytrichum

Leaves with a narrow costa having <20 lamellae.

Lamellae on both surfaces of leaves; leaves unbordered; 5-15 lamina; WC, NW

Oligotrichum

Lamellae restricted to the upper surface of leaves.

Leaves with awns; 2-4 lamellae; plants +bulbiform; WS

Pterygoneurum

Leaves with cilia at leaf shoulder; 5-15 lamellae; WA, BC, AK

Bartramiopsis

Leaves bordered by hyaline, elongate cells; 2-8 lamellae; WS

Atrichum

Leaves bordered by hyaline, short , diagonally oriented cells; 5-15 lamellae; A/A.

Psilopilum

Leaves with ridge -like lamellae on the back (dorsal side) of the costa.

Stems tomentose (wooly; white to rusty brown); alar cells hyaline and yellow -brown; WS

Dicranum

Stems smooth ; alar cells not pigmented.

Costa broad (>1/3 leaf width); ridges weak (1-2 cells); cells short-rectangular; WS

Campylopus

Costa narrow (<1/3 leaf width); ridges strong (>6 cells); cells rounded-oblate; N

Dryptodon

Leaves with green , branched filaments .

Leaves fleshy : filaments on lamina and costa, but covered by inrolled leaf margins; WS*

Aloina

Leaves thin; filaments on costa only; leaf margins reflexed to revolute; W

Crossidium

Leaves with fine, white , threadlike filaments in a tangled, cobwebby weft ; N*

Saelania

Group A11 - Leaves undulate (Skeleton)

Leaves complanate (attached all around the stem but twisted into one plane); E

Aulacomnium

Leaves with lamellae on the costa; WS

Atrichum

Leaves with hyaline, marginal wedges broadest at the base; WS

Tortella

Leaves lacking any of the above unique characteristics; N

Dicranum

Group A12 - Leaves involute (Skeleton)

Leaf margins involute wet or dry.

Leaf margins infolded/inflexed over photosynthetic lamellae or filaments.

Leaves with green, sheet-like lamellae; WS

Polytrichum

Leaves with green, branched filaments; WS*

Aloina

Leaf margins inrolled over laminae lacking lamellae or filaments.

Leaf cells papillose.

Capsules exserted and operculate; WS

Weissia

Capsules immersed to emergent, cleistocarpous; E

Astomum

Leaf cells smooth; laminae +bistratose.

Leaf margins spirally inrolled above a sheathing base; AK

Indusiella

Leaf margins not spirally inrolled; WS

Ptychomitrium

Leaf margins involute when dry ; plane to erect when wet; cells bulging on upper surface.

Leaves +toothed above; costa with two stereid bands; peristome lacking; E

Hyophila

Leaves + entire; costa with one stereid band; peristome present; FL, GA

Plaubella

Group A13 - Leaves +all costa (Skeleton)

Leaves channeled and subtubulose; E

Leucobryum

Leaves flat on the upper side; FL, LA.

Octoblepharum

Group A14 - Leaves with a broad, single costa (Skeleton)

Leaves bristle-like (setaceous) or with distinct hair-points.

Leaves with a costa of 3(4) cell layers (middle layer green; external layers hyaline); N*

Alar cells distinctly inflated; costal stereid cells & brood bodies lacking; N*

Paraleucobryum

Alar cells weakly differentiated; costal stereid cells & brood leaves common; E

Brothera

Leaves crowded at stem tips; reddish, axillary hairs common; WS

Leptobryum

Leaves lacking any of the above unique characteristics

Leaves with strongly differentiated alar cells (inflated and hyaline)

Inner basal cells pale, enlarged and extending up along the costa; N*

Dicranodontium

Inner basal cells little differentiated; WS

Campylopus

Leaves with alar cells little differentiated.

Leaves >3mm; upper cells elongate; MO

Campylopodiella

Leaves <3mm; upper cells rectangular to linear; WS

Dicranella

Leaves oblong -lanceolate ; capsules elongate, curved and with a conspicuous neck.

Upper leaf cells oblong-hexagonal, thin-walled & lax; N

Amblyodon

Upper leaf cells short rectangular, thick-walled & not lax; N

Meesia

Reminder - The costa in Groups A15 through A19 is long and single.

Group A15 - Leaves with bases distinctly incurved to expanded and clasping (Skeleton)

Leaves squarrose - recurved.

Leaves subulate / setaceous; subula roughened throughout by cell ends; N

Trichodon

Leaves ovate- lanceolate, strongly apiculate and with apical teeth; SW

Rhexophyllum

Leaves subulate / setaceous (needle or bristle-like).

Cells intermediate in length and prorulose/papillose ; upper cells + bistratose ; WS

Bartramia

Cells intermediate in length and smooth.

Capsules with distinct, very long necks; WS

Trematodon

Capsules lacking a distinct neck.

Plants minute; peristome double with entire, papillose teeth; NT

Pseudoditrichum

Plants larger ; peristome single with forked teeth.

Teeth divided to base, round and papillose; WS

Ditrichum

Teeth divided to mid - point , flat and pitted - striolate; WS

Dicranella

Cells short and smooth

Upper cells + bistratose; capsules inclined , asymmetric and strumose; WS

Oncophorus

Upper cells unistratose ; capsules erect , symmetric and cylindrical; SW

Symblepharis

Leaves with lamellae or ridges on their laminae or costa.

Leaves with a very broad costa covered by >20 lamellae.

Leaves mostly bistratose; caducous awns ; peristome lacking; A/A

Lyellia

Leaves mostly unistratose; peristome present.

Lamellar apical cells papillose; capsules +terete.

Leaves subtubulose; lamellar apical cells elliptic-pyriform; WS

Polytrichastrum

Leaves oblong lanceolate; lamellar apical cells +rounded; WS

Pogonatum

Lamellar apical cells smooth or ridged; capsules sharply 4-5 angled; WS

Polytrichum

Leaves with a narrow costa having 5-15 lamellae.

Lamellae on both surfaces of leaves; leaves unbordered; WC, NW

Oligotrichum

Lamellae on upper surface of leaves only; cilia at leaf shoulder; WA, BC, AK

Bartramiopsis

Leaves bistratose with spirally inrolled margins; AK

Indusiella

Leaves lacking any of the above unique characteristics; cells strongly bulging on upper surface; endostome of 64 papillose filaments; WS

Timmia

Group A16 - Leaves with long decurrencies (Skeleton)

Plants dendroid; stem leaves bordered with long, marginal, right-angled teeth; WC, NW

Leucolepis

Plants not dendroid.

Shoots angular in cross-section; leaves squarrose recurved; cells short and papillose .

Leaves 3 -ranked ; stems smooth; CA

Triquetrella

Leaves 5 -ranked ; stems densely tomentose ; calcareous wetlands; N

Paludella

Shoots terete (round in cross-section); capsules pyriform or pendulous.

Leaves distinctly toothed +throughout.

Marginal teeth paired; sterile stems +erect and round; WS

Mnium

Marginal teeth single; sterile stems prostrate and complanate; WS

Plagiomnum

Leaves entire to +serrulate or +toothed at apex.

Leaves predominantly broader near the middle; capsules pendent.

Leaves commonly bordered; median cells <4:1; WS

Bryum

Leaves not bordered; median cells >4:1; WS

Pohlia

Leaves predominantly broader at the base; setae very long; capsules +inclined; N

Meesia

Group A17 - Leaves with a distinct group of hyaline cells (Skeleton)

Note 1 - many taxa with short, papillose, medial cells possess basal cells that are somewhat differentiated, i.e., pale (translucent), less papillose, somewhat elongated and/or colored, especially near the insertion. The taxa in this Group A17 represent the extreme, strongly differentiated condition of a gradient while those taxa with the less differentiated basal cells are found in Group A25.

Note 2 - hyaline cells may not be clearly distinct in very old leaves that have lost their chlorophyll.

Hyaline cells at apex of leaves; plants whitish .

Stems often forked or branched, especially at stem apices.

Cells papillose (simple and forked); capsules immersed; peristome lacking; WS

Hedwigia

Cells smooth; capsules exserted with extremely long necks; peristomate; A/A

Plagiobryum

Stems rarely branched; leaves apiculate; capsules pendent; cells smooth; WS

Bryum

Hyaline cells as marginal wedges broadest at the base of leaves.

Leaves squarrose-recurved and serrulate above; upper cells pleuripapillose; S

Pleurochaete

Leaves spreading and crenulate to entire.

Leaves lingulate with rounded-obtuse apices; upper cells bulging; GC

Luisierella

Leaves acute to acuminate; upper cells pleuripapillose; WS

Tortella

Hyaline cells in abruptly differentiated, +oval "windows " (cancellinae) in the lower 1/3 of leaves.

Leaves with linear, intramarginal cells; calyptrae persistent , clasping and split; FL

Calymperes

Leaves lacking linear, intramarginal cells; calyptrae deciduous and cucullate.

Leaf margins revolute; peristome of 32 twisted teeth; 1*; WS

Tortula (Syntrichia}

Leaf margins plane; peristome of 16 straight teeth; 2* ; E(GC)

Syrrhopodon

Hyaline, inflated and thin-walled cells across the lower 1/3 of leaves.#

Leaves abruptly serrate at the shoulder and whorled at branch points; 2*; WS

Eucladium

Leaves toothed above; 2*

Upper leaf cells densely pleuripapillose; capsules smooth; 2*

Older leaves brick-red; stems lacking a hyalodermis; WS

Bryoerythrophyllum

Older leaves brownish-green ; stems with a hyalodermis; BC

Trichostomum

Upper leaf cells smooth; capsules 8-ribbed (dry); E

Rhabdoweisia

Leaves bistratose along margins, in longitudinal rows or +throughout.

Leaf margins erect/involute; calyptrae plicate; peristome 16 +coherent teeth; 2*; WS

Ptychomitrium

Leaves revolute at least below; 1*.

Leaves +rounded with short to long awns; cells 10-13 ; peristome present.

Peristome of 32 twisted teeth on a high basal membrane; WS

Tortula

Peristome of 32 +erect teeth on a low basal membrane; WS

Desmatodon

Leaves +acute; cells 15-20 ; peristome none or rudimentary; WS

Pottia (Microbryum)

Leaves lacking any of the above unique characteristics.

Cross walls of basal cells thick and brown; calyptrae long campanulate; 1* ; WS

Encalypta

Cross walls of normal thickness; calyptrae cucullate.

Stems with a hyalodermis; papillae usually bifid; 2* .

Stems with a central strand (small cells); NW, WC, GC

Trichostomum

Stems lacking a central strand; WS

Trichostomum

Stems lacking a hyalodermis; papillae usually C-shaped; 1*.

Peristome of 32 twisted teeth on a high basal membrane; WS

Tortula

Peristome of 32 +erect teeth on a low basal membrane; WS

Desmatodon

Group A18 - Leaves with a distinct marginal border (Skeleton)

Leaves ciliate at the margins.

Plants primarily protonemata; capsules inclined, ovoid and ventricose; WS*

Buxbaumia

Plants leafy; capsules not differentiated as above.

Leaves with 4-9 lamellae on costa; cilia at leaf shoulder; WA, BC, AK

Bartramiopsis

Leaves lacking lamellae; cilia at leaf base; WA, AK

Oedipodium

Leaves with a border of elongate cells contrasting with shorter medial cells.

Plants dendroid; stem leaves bordered with long, marginal, right-angled teeth; WC, NW

Leucolepis

Plants erect, rosulate -foliate and large; from horizontal, underground stems; WS

Rhodobryum

Plants strongly flattened; leaves twisted into one plane (complanate); WS

Plagiomnium

Plants with red stems.

Stems tomentose.

Rhizoidal initials in longitudinal rows; endostome fused into a dome; N

Cinclidium

Rhizoidal initials not in rows; endostome segments free; N*

Rhizomnium

Stems smooth.

Leaves +rugose; cells thin-walled and very large (to 150x50µ); WC, NW, CO

Roellia

Leaves 4 -ranked and dimorphic (dorsal leaves smaller); WC

Epipterygium

Leaves lacking the above unique characteristics; cells strongly bulging; AK

Trachycystis

Plants lacking the above unique characteristics.

Leaves with lamellae on the costa; WS

Atrichum

Leaves with abruptly differentiated cancellinae (hyaline basal cells); E (GC)

Syrrhopodon

Leaves with paired teeth on margins; WS

Mnium

Leaves with distinct single teeth or serrulations on margins.

Leaf cells >3:1.

Leaves rounded-obtuse and apiculate; upper cells in oblique rows; N*

Pseudobryum

Leaves acute to awned; cells not in oblique rows.

Capsules pendent and pyriform; WS

Bryum

Capsules erect and +cylindric; GC, SW, SA

Brachymenium

Leaf cells <2:1; WS

Plagiomnium

Leaves with entire margins.

Leaf cells >3:1.

Capsules pendent and pyriform; WS

Bryum

Capsules erect.

Leaves rounded-obtuse; upper cells in oblique rows; N*

Pseudobryum

Leaves broadly acute; cells not in oblique rows; WS

Entosthodon

Leaf cells 1-2:1; A/A

Cyrtomnium

Leaves bordered by hyaline , diagonally oriented cells; 5-15 lamellae on costa; A/A.

Psilopilum

Leaves with short-rhombic marginal cells at the rounded-obtuse apex; GC, SW

Splachnobryum

Leaves with margins differing in color and/or opacity from the medial laminae.

Margin darker because 3-5 cell layers thick; plants blackish; on rocks in rivers; WC, NW

Scouleria

Margin paler and yellowish due to thick -walled, less papillose cells.

Leaves distinctly toothed above; basal membrane lacking ; 2* ; SE

Leptodontium

Leaves entire; basal membrane present; 1*.

Peristome (32) spirally twisted above a high basal membrane; WS

Tortula

Peristome (16) obliquely slanted above a low basal membrane; WS

Desmatodon

Margin greener (cells thin -walled and less papillose) and spirally revolute; 1*; WC, SW

Pseudocrossidium

Leaves with an intramarginal "border", i.e., differentiated cells just inside short marginal cells.

"Border" of long, narrow, pellucid cells along leaf bases.

Basal cancellinae (hyaline, inflated cells) present; plants green; on soil; FL

Calymperes

Basal cancellinae lacking; plants blackish; on rocks in rivers; WC, NW

Scouleria

"Border" of enlarged, +isodiametric, yellow to orange, thick-walled cells. 1*; W

Crumia

Group A19 - Leaves with distinct alar cells (Skeleton)

Stems tomentose; alar cells inflated, hyaline and +yellow-brown towards the margin; WS

Dicranum

Stems not or indistinctly tomentose; alar cells not as above.

Costa broad, >1/3 leaf width; alar cells inflated , and hyaline to brownish to reddish.

Costa 3(4) cell layers thick (middle layer green; external layers hyaline); N*

Paraleucobryum

Costa lacking the above unique characters.

Inner basal cells pale, enlarged and extending up along the costa; N*

Dicranodontium

Inner basal cells little differentiated; WS

Campylopus

Costa narrow, <1/3 leaf width.

Alar cells enlarged to inflated and yellowish to brownish.

Capsules curved and strumose (goiter-like swellings); A/A

Kiaeria

Capsules obovoid to pyriform; on rocks.

Capsules ribbed (dry); peristome teeth wide-flaring, +split and striolate; N

Arctoa

Capsules smooth (dry); peristome teeth erect, +entire and papillose; N*

Blindia

Capsules cylindrical; substrates various.

Cells with cuticular ridges; peristome teeth +entire and papillose; N*

Dicranoweisia

Cells smooth; peristome teeth forked and pitted-striolate below; WS

Dicranum

Alar cells sub-quadrate and pale; cells +thick -walled and often nodulose; WS

Grimmia

Group A20 - Leaves with costa extremely reduced to lacking (Skeleton)

Leaves in clusters of branches around a central stem and a network of green and hyaline cells; WS

Sphagnum

Leaves distichous , decurrent and confluent ; protonemata luminous ; Goblin Gold ; WS*

Schistostega

Leaves complanate; cells pleuripapillose; on tree bark; GC

Erpodium

Leaves awned; cells smooth; on tree bark .

Leaves with conspicuous primordial utricles ; peristome lacking; TX

Erpodium

Leaves lacking utricles; peristome present; OK and TX

Venturiella

Leaves spinose serrate; protonemata persistent; cells smooth; pygmy ephemerals; WS

Ephemerum

Leaves lacking the above unique characters.

Cells papillose; capsules exserted and valvate (4x); plants reddish-black; on rocks; N*

Andreaea

Cells smooth.

Capsules exserted with 4 prominent teeth; on undersides of rock overhangs; N

Tetrodontium

Capsules sessile and gymnostomous ; pygmy ephemerals; on soil; WS

Micromitrium

Reminder - Definitions for cell length to breadth ratios are found in the Introduction, the Overview and at the end of this page. Abbreviations for the number of stereid bands in costa cross sections are found in the Introduction and at the end of this page. An expanded explanation of the difference between "Distinct" and "Indistinct" surface ornamentation is found in the Introduction.

Group A21 - Cells long (>5:1) and smooth (Skeleton)

Leaves flexuose-twisted (dry); cell walls +thickened ; capsules mostly erect; SA, CA

Orthodontium

Leaves little altered (dry); cell walls not thickened; capsules inclined to pendulous; WS

Pohlia

Group A22 - Cells intermediate (2-5:1) and distinctly papillose (Skeleton)

Leaves broadly spathulate with rounded , crenulate apices; papillae C-shaped; FL

Gymnostomiella

Leaves ovate and abruptly narrowed to a short acumen; papillae simple; W, VT

Philonotis

Leaves linear-lanceolate to subulate from an erect base; papillae simple; WS

Bartramia

Group A23 - Cells intermediate (2-5:1) and distinctly prorulose (Skeleton)

Leaves julaceous and 5-ranked ; peristome teeth fused at tip; A/A

Conostomum

Leaves and peristome teeth otherwise.

Setae flexuose; capsules symmetric and rugulose; peristome reduced; NC, TN

Bartramidula

Setae straight; capsules asymmetric and furrowed; peristome teeth lanceolate.

Leaves with bistratose margins and/or lamina; mesic habitats; WS

Bartramia

Leaves unistratose; hydric habitats; WS

Philonotis

Setae short, capsules immersed.

Leaves +linear-lanceolate and +spinulose above; protonemata persistent; WS

Ephemerum

Leaves +subulate and serrulate above; protonemata ephemeral; WS

Bruchia

Group A24 - Cells intermediate and smooth (or indistinctly ornamented#) (Skeleton)

Leaves predominantly broader near or above the middle (+oblong or obovate).

Plants small, winter annuals on soil.

Capsules clearly exserted.

Costa strong; protonemata ephemeral ; peristome lacking; WS

Physcomitrium

Costa weak; protonemata persistent ; peristome present; WS*

Discelium

Capsules +immersed and +pyriform .

Leaves +concave-obovate and serrulate; capsules operculate; WS

Physcomitrium

Leaves +concave-ovate and entire; capsules cleistocarpous; WS

Bruchia

Plants otherwise .

Leaves with an obtuse apex bordered with short -rhombic cells; GC, SW

Splachnobryum

Leaves commonly bordered by linear cells; capsules pyriform and pendent; WS

Bryum

Leaves unbordered.

Medial cells strongly bulging on both sides; AK

Bryobrittonia

Medial cells smooth and >5:1 (linear rhomboidal); capsules pendent; WS

Pohlia

Medial cells smooth and <4:1 ; capsules inclined to erect.

Peristome of 4 massive teeth; plants bud-like ; costa weak; on rocks; N

Tetrodontium

Peristome of 16 teeth; costa strong; on soil.

Capsules with well-differentiated necks; calyptrae mitrate; N*

Tayloria

Capsules lacking a distinctive neck; calyptrae inflated cucullate.

Capsules inclined and asymmetric; WS

Funaria

Capsules erect and symmetric ; WS

Entosthodon

Peristome lacking; capsules erect and symmetric; calyptrae mitrate; WS

Physcomitrium

Leaves predominantly broader near the base (+lanceolate).

Plants small, winter annuals on soil; capsules +immersed and cleistocarpous; WS

Bruchia

Plants otherwise; capsules exserted and peristomate.

Leaves +subulate / setaceous.

Capsules ovoid; plants minute to very small; on calcareous rocks; WS (N)

Seligeria

Capsules long cylindric; peristome teeth round, fully split and papillose; WS

Ditrichum

Capsules +oblong, often curved ; peristome teeth flat , split 1/2 and pitted; WS

Dicranella

Leaves flexuose-twisted (dry); cells +thick-walled; SA, WC

Orthodontium

Leaves with expanded, sheathing leaf bases; WS

Dicranella

Leaves lacking any of the above unique characteristics.

Leaves >1mm; capsules terminal.

Costa percurrent; capsules erect; peristome single.

Upper cells +linear; peristome teeth long & split; WS

Ditrichum

Upper cells broad; peristome teeth short & irregular; N

Catoscopium

Costa subpercurrent; capsules +pendant; peristome double; WS

Pohlia

Leaves <1mm; capsules lateral; peristome single; on Cu or S rich soils; N*

Mielichhoferia

# Note - cells bulging, mammillose (both bulging and papillose) or indistinctly papillose, i.e., low papillae.


Group A25 - Cells short (<2:1) and distinctly papillose (Skeleton)

Leaves with expanded , sheathing bases; cells strongly bulging on upper surface; WS

Timmia

Leaves distinctly toothed in the upper half.

Cells pleuripapillose ; leaves +squarrose -recurved; 2*.

Leaf lamina +bistratose; stem hyalodermis present; peristome lacking; SW

Rhexophyllum

Leaf lamina unistratose; stem hyalodermis lacking; peristome present; SE

Leptodontium

Cells unipapillose or mammillose; ventral stereid band weak or lacking.

Leaves +broad; cells mammillose; capsules smooth; WS

Dichodontium

Leaves +narrow; cells coarsely papillose; capsules furrowed; N

Cynodontium

Leaves with large, curved, projecting papillae at extreme apex; cells mammillose: NW

Dichodontium

Leaves ligulate and rounded-obtuse ; cells pleuripapillose ; 0* ; WS*

Gyroweisia

Leaves with revolute margins and smoother , greener marginal cells; 1* ; WC, SW

Pseudocrossidium

Leaves lacking the above unique characteristics.

Cells collenchymatous and stellate; 2* .

Leaves squarrose -recurved (wet); cells pleuripapillose; A/A

Didymodon

Leaves +erect (wet); cells unipapillose; A/A

Aulacomnium

Cells pleuripapillose; but neither collenchymatous nor stellate.

Papillae flower-like (massive and multifid); peristome lacking; 2* ; SE

Tuerckheimia

Papillae forked; basal cells with brown cross-walls; calyptrae long-cylindric; WS

Encalypta

Papillae C-shaped.

Basal cells with brown cross-walls; calyptrae long-cylindric; 1*; WS

Encalypta

Basal cell walls uncolored; calyptrae cucullate.

Peristome teeth long and twisted; 2* ; WS

Barbula

Peristome teeth short and erect; 1* ; WS

Desmatodon

Papillae conical.

Cells with 4-7 papillae; peristome reduced to lacking.

Stems repeatedly forked; capsules elongate and urn-shaped; 2 *; WS

Amphidium

Stems sparsely forked; capsules +pyriform; 1 * or lacking; WS*

Zygodon

Cells with 1-4 papillae.

Costa with two stereid bands.

Leaf margins revolute on both sides; peristome present.

Papillae crowded; basal cells hyaline; peristome twisted; WS

Barbula

Papillae scattered; basal cells green; peristome +oblique; WS

Didymodon

Leaf margins revolute on one side only; peristome lacking; WS

Hymenostylium

Leaf margins plane; peristome lacking .

Leaves >2 mm; sporophytes lateral; A/A

Molendoa

Leaves <2 mm; sporophytes terminal; WS

Gymnostomum

Costa with one stereid band; peristome lacking.

Sporophytes lateral; stem rounded-triangular; WS

Anoectangium

Sporophytes terminal; stem round ; WS

Gymnostomum

Costa lacking stereid bands; peristome present.

Basal marginal cells with thickened cross-walls; WS

Ulota

Basal marginal cells +undifferentiated; WS

Orthotrichum

Cells unipapillose; but neither collenchymatous nor stellate.

Leaves serrulate at apex; stems tomentose; gemmae on stem extensions; WS

Aulacomnium

Leaves entire.

Capsules exserted; peristome of 32 twisted teeth ; plants on soil and rocks; 2*; WS

Barbula

Capsules +emergent and valvate (4x); blackish plants on rocks; 0* ; N*

Andreaea

Capsules +immersed with 16 +reflexed teeth; plants on trees and rocks; 0* .

Basal marginal cells with thickened cross-walls; WS

Ulota

Basal marginal cells +undifferentiated; WS

Orthotrichum

Group A26 - Cells short (<2:1) and smooth (or indistinctly ornamented#) (Skeleton)

Leaves +obovate (broadest in upper third; shaped like an upside-down egg), concave and broadly obtuse; 1* .

Leaves cucullate; costa subpercurrent; TX

Globulinella

Leaves muticous to piliferous; costa subpercurrent to excurrent; NW

Stegonia

Leaves +oblong-spathulate (broad in the middle and even broader above).

Leaf margins inrolled when dry (erect or plane when wet); cells bulging on upper surface.

Leaves 1.5 -3 mm and +toothed above; peristome lacking; 2*; E

Hyophila

Leaves 1 -2 mm and +entire above; peristome present; 1*; FL, GA

Plaubella

Leaf margins usually revolute, at least in part; cells flat.

Leaves +bordered with longer cells; peristome teeth short and erect; 1* ; WS

Desmatodon

Leaves +bordered with shorter cells; peristome teeth long and twisted; 1* ; WS

Tortula

Leaves with intra -marginal border of enlarged, thick -walled , orange cells; 1* ; W

Crumia

Leaves unbordered.

Propagula on basal leaf surfaces ; sporophytes unknown; 1*; SE

Rhacithecium

Propagula axillary; peristome of 32 spirally twisted teeth; 2* ; WS

Barbula

Leaf margins plane; cells flat and large (> 15); peristome none or rudimentary; 1* ; WS

Pottia

Leaves +oblong-lingulate (tongue-shaped)or oblong-ligulate (strap-shaped).

Leaves +lingulate; cells 2(3)stratose; awns on perichaetial leaves; capsules sessile; E, BC

Diphyscium

Leaves +ligulate ; cells unistratose; perichaetial leaves +acute; capsules exserted.

Leaves acute; capsules gymnostomous (lacking a peristome); 1* ; WS

Scopelophila

Leaves obtuse; capsules peristomate (peristome present); 0*; WS*

Gyroweisia

Leaves +ovate (broadest in lower third; egg-shaped) and revolute; peristome of 32 teeth; 2*; WS

Barbula

Leaves ovate-lanceolate to lanceolate (broadest near the base; lance-shaped).

Leaves 3-ranked; setae very long; plants of calcareous wetlands; N

Meesia

Leaves falcate -secund ; capsules valvate ; plants saxicolous and blackish; NW

Andreaeobryum

Leaves with expanded, sheathing leaf bases.

Cells bulging on upper surface; capsules symmetric and oblong -ovoid; WS

Timmia

Cells smooth; capsules asymmetric and strumose (goiter-like swelling); WS

Oncophorus

Leaves with paired teeth on bistratose margins.

Margins revolute below; cells with cuticular ridges; perichaetia terminal; N*

Plagiopus

Margins plane; cells smooth; perichaetia lateral (basal); GC

Pyrrhobryum

Leaves with an intramarginal band of long, narrow cells at base; WC and NW

Scouleria

Leaves bistratose, at least in part.

Leaf cells strongly bulging on upper surface & unistratose at margins; 2*; WC, SW, TX

Timmiella

Leaf cells smooth to +bulging/papillose & bistratose at margins.

Leaf margins erect/involute; calyptrae mitrate, lobed and plicate; 2* ; WS

Ptychomitrium

Leaf margins plane; calyptrae cucullate, entire and smooth; 1* ; WC, AZ

Didymodon

Leaves lacking any of the above unique characters.

Capsules split along 4 sutures; plants saxicolous and blackish; N*

Andreaea

Capsules with 4, massive teeth; leaves pellucid ; terminal gemmae cups; WS

Tetraphis

Capsules with 8, 16 or 32 lanceolate teeth.

Plants in tufts on tree trunks (rarely on rocks); diplolepideous.

Leaves crisped when dry; basal cells yellow, thick -walled; WC

Ulota

Leaves not crisped when dry; basal cells +undifferentiated; WS*

Orthotrichum

Plants in tufts, cushions or mats on rocks.

Peristomes diplolepideous (double).

Basal cells very thick -walled, yellow and radiating from costa; WS

Ulota

Basal cells +thick -walled, neither yellow and nor radiating; WS

Orthotrichum

Peristomes haplolepideous (single).

Plants very small (<2 mm); setae cygneous (wet); N

Seligeria

Plants larger (>2 mm).

Capsules systylious; calyptrae short; in wetter habitats; WS

Schistidium

Capsules not systylious; calyptrae longer; in dryer habitats; WS

Grimmia

Plants on soil primarily.

Setae cygneous.

Capsules yellow-orange with red ribs; calyptrae cucullate; A/A

Oreas

Capsules yellowish and smooth; calyptrae mitrate; N*

Campylostelium

Setae bent at capsule base; capsules curved, sulcate, +strumose & purple-red (yellow); leaves revolute

Ceratodon

+throughout & serrate apically; upper cells +square; WS

Setae straight.

Capsules ribbed; in crevices of cliffs and boulders.

Peristome teeth divided to half their length; N

Cynodontium

Peristome teeth undivided; basal cells hyaline; E

Rhabdoweisia

Capsules smooth (or wrinkled when dry).

Setae very long; capsules inclined; peristome double; in fens; N

Meesia

Setae shorter; capsules erect; peristome single; on mineral soils.

Basal cells hyaline; peristome teeth twisted; WS

Barbula

Basal cells green; peristome teeth +oblique; WS

Didymodon

# Note - cells bulging, mammillose (both bulging and papillose) or indistinctly papillose, i.e., low papillae.



Cells = medial, laminal cells; cells ~2/3 of the way from insertion to apex, midway between the costa and the margin.

Cell length to breadth ratio:

Long cells: >5:1; commonly termed linear.

Intermediate cells: 2-5:1; commonly termed elongated, rectangular, hexagonal, or rhomboidal.

Short cells: <2:1; commonly termed isodiametric, quadrate, rounded-quadrate, or sub-quadrate.

Number of stereid bands evident in costa cross-sections:

2* = costa with two stereid bands

1* = costa with one stereid band

0* = costa lacking stereid bands, i.e., +homogeneous


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