Exostome teeth usually with oblique cross-walls connecting lamellae, exostome partially united to endostome; spores

usually > 40 µm; endostome segments with narrow, slit-like perforations; border less conspicuous, only locally bistratose; plants sometimes pale reddish. . . .

. . . .Ptychostomum warneum (Bryum warneum) (n.s.)

– Exostome teeth without cross-walls between lamellae, endostome free; spores smaller, 28 (35) µm; endostome segments with oval perforations; leaf margin with yellowish, conspicuous regularly bistratose border; seta to 5 cm long;

plants green. . .

. . . .Ptychostomum cernuum (Bryum uliginosum) (n.s.)

33(29) Leaf margin without border or border indistinct. . . .34 – Leaf margin with distinct border. . . .36 34 Capsule with narrow mouth, elongate pyriform mostly slightly asymmetric, gibbous, red-brown to blackish when ripe; cilia of variable length, nodose, not appendiculate;

plants synoicous; spores 18–25 µm. . . .

. . . .Ptychostomum intermedium (Bryum intermedium) (rr)

– Capsule with wide mouth, cilia appendiculate, or plants without capsules, dioicous. . . .35

35 Plants small, 0.5–1 cm tall, whitish-green, julaceous; leaves broadly ovate, strongly concave, imbricate, crowded at bud-like apex; costa excurrent as short, but stout apiculus (of ca 10% of total leaf length or less), 60–100 µm wide at leaf base; lamina cells thin-walled, lax, 20–35 × 15 µm; marginal border lacking (or consisting of a single row of incrassate, hardly narrowed cells); capsule turbinate (strongly contracted below mouth) when dry and empty. . . .

. . . .Ptychostomum funkii (Bryum funckii) (rr)

– Plants not bud-like, taller, 0.5–2 cm; leaves ovate to ovate-lanceolate, not strongly concave, gradually narrowed to long point formed by excurrent costa (of ca 20–30% of total leaf length), entire or weakly denticulate; lamina cells longer, 40–70 µm long; leaves enlarged and crowded towards shoot apex; leaf margin recurved to revolute from base to near apex; margin with ± indistinct border formed by 2–3 (4) rows of elongate, narrow cells; plants dioicous, but often with sporophytes; capsule wide-mouthed, pendulous; cilia long appendiculate; spores 10–12 µm. . . .

. . . .Ptychostomum imbricatulum (Bryum caespiticium) (c)

36(33) Plants without sporophytes. . . .

. . . .plants cannot be identified without ripe capsules

– Plants with ripe capsules. . . .37 37 Cilia short to rudimentary; spores large, usually > 20 µm (18–50 µm); plants usually synoicous; capsule narrow-mouthed. . . .38 – Cilia long, nodose or appendiculate; spores small, usually <

20 µm (10–24 µm); plants dioicous, synoicous, autoicous or polyoicous; capsule mouth wide or narrow. . . .39 38 Exostome teeth with oblique cross-walls between lamellae;

endostome attached to exostome; lid with sharp point; costa longly excurrent. . .

. . . .Ptychostomum compactum (Bryum algovicum) (r)

Note: Compare also P. warneum.

– Exostome teeth usually without cross-walls; endostome free; capsule obovate to pyriform; lid flat, mamilla indistinct;

leaves ovate-lanceolate, upper leaves longly acuminate;

costa excurrent into long, smooth or slightly denticulate cuspidate point; exostome teeth at tip with thickened cell wall remnants. . . .Ptychostomum inclinatum

(Bryum archangelicum, B. imbricatum) (rr) 39 Spores 15–25 µm; capsule mouth wide or narrow. . . .40 – Spores (at least majority) not exceding 16 µm; capsule large-mouthed. . . .41 40 Capsules ± gibbous, elongate pyriform, mostly somewhat curved and asymmetric, narrow-mouthed, cernuous to pendulous; leaf margin with indistinct border or 2–3 rows of narrow, elongate cells; plants synoicous. . . .

. . . .Ptychostomum intermedium (Bryum intermedium) (rr)

– Capsules cylindrical to clavate pyriform or elongate pyriform, not curved, symmetric, large-mouthed, sometimes inclined; leaf margin with distinct border of 2–6 rows of elongate, narrow incrassate cells; plants autoicous or polyoicous. . . .Ptychostomum pallescens

(Bryum pallescens agg., incl. B. lonchocaulon) (r) 41 Plants synoicous; red leaf base distinct, leaf margin with distinct border of narrow, elongate, incrassate cells. . . .

. . . .Ptychostomum creberrimum (Bryum creberrimum) (r)

– Plants dioicous; leaf base often concolorous to indistinctly red; leaf margin with few rows of narrow, elongate cells forming indistinct border. . . .

. . . .Ptychostomum imbricatulum (Bryum caespiticium) (c)

Key to species of Pohlia

References: Erzberger (2005), Guerra in Guerra et al. (2010)

1 Plants rarely with sporophytes; usually with numerous axillary gemmae (bulbils) in leaf axils in upper part of stem, rarely bulbils solitary (in P. andalusica); lamina cells 8–10 times as long as wide; costa reaching leaf apex; leaf margin weakly denticulate at apex. (Pohlia annotina agg.). . . .2 – Plants without axillary bulbils. . . .5 2 Bulbils globose to slightly elongate, rarely more than twice

as long as wide, mostly (70) 80–130 (175) µm × 60–110 (150) µm, usually stalked, leaf primordia poorly formed, peg-like, incurved, consisting of only 1 (2) cell(s), never laminate; bulbils yellow-translucent, occasionally brown;

plants dull when dry. . . .Pohlia camptotrachela (n.s.) – Bulbils oblong, obconic or elongate and vermicular; plants dull or glossy. . . .3

3 Leaf primordia distinctly laminate in form; bulbils (including primordia) usually narrowed towards the apex and the base in outline, not larger than 600 µm, yellowish-green when young, red-brown when mature; leaf primordia 3–5 (8), laminate, erect, comprising ca 1/2 of total bulbil length, inserted at the same level at flattened bulbil apex; plants glossy, leaves straight, appressed to erect when dry. . . . . . . .Pohlia andalusica (rr) – Leaf primordia peg-like, rarely becoming laminate on very large ovate bulbils; bulbils green, yellow, orange, red according to age; plants dull or glossy. . . .4 4 Plants glossy when dry; bulbils mostly 150–300 (450) µm

long and to 60 µm wide, rather uniform in shape, oblong-linear to oblong-linear-vermicular; leaf primordia 1–2, reaching 1/4 of total bulbil length. . . .Pohlia proligera (rr)

Note: The bulbils of this plant differ from those of P. annotina, which may be similar, by the following characters: body of the bulbil 1–2 cells wide, with 1–2 primordia consisting of 1–2 cells (P. annotina: bulbil body opaque, more than 2 cells wide, with 2–3 (4) leaf primordia mostly consisting of more than 2 cells. See photographs in Guerra et al. (2010), p.

192.

– Plants dull when dry; bulbils extremely variable in size and shape, obovate, obconic to elongate and narrowly turbinate, occasionally bulbiform, rarely vermicular, different forms often present on a single stem, mostly more than 80 µm wide at the broadest point and 150–300 (550) µm long, opaque, with (2) 3–4 (5) peg-like, erect primordia (occasionally becoming laminate with age); leaves patent when dry; leaf cells uniformly wide from costa to margin. . . . . . . .Pohlia annotina (r) 5(1) Capsules longly cylindric, with neck as long as or longer than urn, horizontal; leaves narrowly lanceolate, margins recurved, denticulate; costa excurrent. . . . . . . .Pohlia elongata (n.s.) – Capsules shortly cylindric to ovoid, with shorter neck,

drooping, pendulous. . . .6 6 Lamina cells of upper leaves to 5–6 times as long as wide, mostly > 16 µm wide; vegetative leaves short, only 2–4 times as long as wide; stems and leaf base often reddish. . . .7 – Lamina cells of upper leaves longer, 6–14 µm wide; leaves mostly > 4 times as long as wide; leaf base reddish or not. . . . .8

7 Plants whitish green, with waxy water-repellent surface;

leaves predominantly ovate (observe older stems), ± distinctly decurrent; usually 1–3 cm high plants; rarely with sporophytes. . . .Pohlia wahlenbergii (w) – Plants brownish or pale green, not waxy, easily wetted;

leaves lanceolate to ovate-lanceolate, hardly decurrent;

plants only to 5 mm tall; occasionally with sporophytes. . . . . . . .Pohlia melanodon (c) 8 Plants with rhizoidal gemmae, usually sterile, rarely > 1 cm tall. . . .9 – Plants without rhizoidal gemmae, usually > 1 cm tall. . . .10 9 Gemmae brownish, spherical to pyriform, with smooth surface, not knobbly, 75–150 × 70–90 µm; plants very small, only to 5 mm high; lower leaves lanceolate with costa ending below leaf apex, upper leaves narrowly lanceolate with costa excurrent; lamina cells very narrow and elongate, 70–120 × 9–12 (15) µm. . . .Pohlia lescuriana (r)

Note: rhizoidal gemmae must be well soaked when examining dried specimens, because when insufficiently hydrated they may have protuberant cells. Care must also be taken not to confuse this species with Dicranella rufescens. In P. lescuriana, the marginal cells are slightly narrower than median leaf cells, whereas in D. rufescens they are sometimes even wider.

– Gemmae yellowish, rounded, with protuberant cells giving a knobbly appearance, 50–70 × 40–50 µm; leaf apices more strongly denticulate and lamina cells narrower and longer than in preceding species, 70–180 × 6–10 µm, wider in lower leaves. . . .Pohlia lutescens (w) 10 Lamina cells very long and narrow, about 10 times as long as

wide, 6–10 µm wide and up to 150 µm long; plants conspicuously glaucous green with metallic sheen; leaf base, stem and costa reddish; capsules cernuous, ellipsoid, neck half as long as urn, pale brown. . . .Pohlia cruda (w) – Lamina cells shorter and wider, only 5–7 times as long as

wide, 10–12 µm wide and up to 70 µm long; capsule yellowish brown, elongate pyriform to elliptical; leaves erect, lanceolate, denticulate at apex. . . .11 11 Plants paroicous, spores 20–25 µm in diameter; habitat various, also in wetlands. . . .12 Plants dioicous. spores 10–12 µm in diameter, nearly smooth; growing exclusively in bogs. . . .Pohlia sphagnicola

Note: doubtfully recorded.

12 Plants dark green. . . .Pohlia nutans subsp. nutans (c) – Plants with variegated red, dense shoots, leaves red or at

least with red costa. . .

. . . .Pohlia nutans subsp. schimperi (Pohlia schimperi) (r)

Key to species of Mnium (1; 4–7), Plagiomnium (8–13), Rhizomnium (2)

References: Koponen in Nyholm (1993), Sauer in Nebel and Philippi (2001)

1 Leaves unbordered, bluntly toothed down to mid-leaf. . . . . . .Mnium stellare (w) – Leaves with a border of narrow elongate cells, often multistratose. . . .2 2 Leaf margins entire, leaves roundish oval; stems densely

tomentose in lower part. . . .Rhizomnium punctatum (w) – Leaf margins toothed. . . .3 3 Teeth of leaf margins usually in pairs (geminate); sterile shoots erect, leaves spirally arranged. Mnium pp.. . . .4 – Teeth of leaf margins simple; sterile shoots procumbent or arcuate, with complanate leaves. Plagiomnium. . . .8 4 Lamina cells 13–17 µm wide. . . .Mnium thomsonii (rr) – Lamina cells wider. . . .5 5 Leaves ca twice as long as wide, broadly lanceolate to obovate; lamina cells without collenchymatous thickenings, not arranged in distinct rows; stems with terminal rosettes;

often more than 1 seta per perichaetium; synoicous; leaves flexuose when dry, nearly smooth and only very slightly undulate when moist; dorsal surface of costa usually without teeth, rarely with few teeth; peristome (exostome) dark red-brown. . . .Mnium spinulosum (n.s.) – Leaves at least 3 times as long as wide, lanceolate; lamina cells with or without collenchymatous thickenings; leaves equal in size along stem, not forming rosette; only 1 seta per perichaetium; synoicous or dioicous; peristome (exostome) yellowish, greenish-yellow or brownish to golden-brown, not dark red-brown. . . .6 6 Dorsal surface of costa with teeth; dioicous. . . .7

– Dorsal surface of costa without teeth (a few sometimes present in upper leaves); costa reaching into ± cuspidate leaf apex; cell corners with distinct thickenings; marginal teeth small and blunt; stems and leaf base often brownish;

synoicous. . . .Mnium marginatum (w) 7 Leaf base not decurrent (or decurrent leaf bases not easily seen); costa usually ending below leaf apex (except sometimes in the uppermost leaves); lamina cells without collenchymatous thickenings. . . .Mnium hornum (r) – Leaf base distinctly decurrent; costa ending in acute apex;

lamina cells with collenchymatous thickenings; cells at costa much larger than cells at leaf margin; numerous sharp teeth usually present on dorsal side of costa of all well-developed leaves; marginal teeth sharp. . . .Mnium lycopodioides (r) 8(3) Leaves narrowly lingulate (except in immature plants), conspicuously decurrent; transversely undulate when wet and dry; leaf cells 10–16 µm wide. . . .

. . . .Plagiomnium undulatum (c)

– Leaves orbicular to oval or ovate, decurrent or not, not transversely undulate; leaf cells larger. . . .9 9 Leaves serrate down to mid-leaf. . . .

. . . .Plagiomnium cuspidatum (c)

– Leaves serrate down to base. . . .10 10 Leaf base decurrent along stem. . . .11 – Leaf base not decurrent. . . .13 11 Synoicous, often with sporophytes; lamina cells isodiametric, with thickenings. . .Plagiomnium medium (n.s.) – Dioicous; lamina cells longer than wide, without thickenings

. . . .12 12 Leaves narrowly and often only shortly decurrent; sterile shoots prostrate; lamina cells 1.5–2 times as long as wide;

costa weak, often ending below leaf apex; at least some teeth nearly perpendicular to margin, formed by 1–3 (4) cells. . . . . . .Plagiomnium affine (c) – Leaves longly and broadly decurrent; sterile shoots arcuate;

lamina cells twice as long as wide; costa strong apically, percurrent to excurrent; marginal teeth directed forward and formed by 1–2 cells. . . .Plagiomnium elatum (w) 13 Synoicous; lid longly rostrate; lamina cells not porose, isodiametric to shortly elongate, 35–50 × 20–32 µm, with