Bryaceae. Genus Bryum

1. Leaves widest in upper half, slightly concave to plane, twisted, and spirally contorted along the stems when dry; apices filiform-attenuate; leaf borders 1–3(–4)-seriate, unistratose 2

— Leaves widest in lower half, if widest at midleaf then leaves strongly concave or not twisted and spirally contorted, or not filiform-attenuate, or leaf border absent or partly bistratose 4

2. Brown brood filaments present in leaf axils 30. B. moravicum

The presence of patent leaves and numerous axillary brood filaments greatly help in recognizingBryum moravicum. This species has often been treated as B. flaccidum, or B. capillare var. flaccidum or B. laevifilum. It is fairly widespread throughout Russia, except for the Arctic regions and grows on tree (usually broad-leafed) trunks, sometimes rocks, and occasionally soil.

— Brood filaments absent 3

3. Plants dioicous 13. B. capillare

Bryum capillare is a variable species. The phenotype from sandy soils in pine forests characteristically has loose, soft, dark-green tufts. Ithas short (ca. 1 cm high) fertile shoots and long (ca. 1.5–2 cm) sterile shoots that are more loosely foliate than the fertile shoots. These plants have curved to twisted leaves and long (ca. 4 mm long) capsules, with necks that are indistinctly differentiated from the urns. It grows in forests, forest edges, and more rarely in open places on bare soil, rocks covered with soil, and rarely rotten wood.

— Plants synoicous 48. B. torquescens

Bryum torquescens is similar to B. capillare in many ways, but differs in having synoicous rather than dioicous plants. This is a rare species in Russia, known only from the Black Sea coastal areas of the Caucasus, where it grows on fine soil over rocky substrates.

4. Shoots imbricate; leaves broadest near midleaf, strongly concave, usually more than 1 mm long; filiform acumina or excurrent costae reflexed when dry; leaf border unistratose; rhizoids coarsely, densely papillose; plants green 19.B. elegans

Bryum elegans is distinguished by the following combination of features: pure green plants; shoots often bud-like with closely imbricate, strongly concave leaves; and reflexed leaf apices. It grows on soil and occasionally rocks throughout Russia. Some populations from calcareous substrates in Volgograd and Pskov Provinces have fragile, subterminal shoots that probably are environmentally induced. In Russia this species has never been found with capsules or rhizoidal gemmae.

— Shoots not imbricate, or leaves broadest in lower half, or leaves plane, or leaves less than 1 mm long, or acumina not reflexed, or leaf border partly bistratose, or rhizoids not coarsely papillose, or plants red-colored, variegate or whitish 5

5. Leaves extremely longly and broadly decurrent, the decurrency nearly as long as the leaf; leaf borders nearly absent, unistratose; plants hygrophilous, medium to large-sized, 1.5–10 cm high 53.B. weigelii

This species can be recognized by its unbordered or nearly unbordered leaves and remarkably long, broad leaf decurrencies. It has a scattered distribution throughout the lowland regions of Russia where it occurs on muddy or peat soil in swampy meadows and eutrophic swamps, the banks of irrigative channels, near springs, and along streams in forests.

— Leaves not or shortly decurrent; leaf borders uni- or multistratose; plants usually mesophilous, small- to large-sized 6

6. Plants whitish to pale green and silvery 7.B. argenteum

Bryum argenteum is distinguishable, even when sterile, by the combination of its whitish or glaucousr color and small, distinctly julaceous plants. Its short, strongly concave leaves are usually hyaline above and have subpercurrent costae. A few other Russian species of Bryum are also whitish in color, however, they differ from B. argenteum in apical leaf form (non-filiform vs. filiform), costae strength (excurrent vs. subpercurrent), and leaf border form (distinctly bordered vs. unbordered or indistinctly bordered). Plants of B. argenteum from xeric habitats have leaves with a more extensive hyaline upper part, longer, piliferous acumina, and the costae often filling the acumen or excurrent. These phenotypes are sometimes segregated as the var. lanatum;however, they occur throughout Russia and appear to represent ecological variants that hardly warrant taxonomic recognition.

— Plants green, yellow, brown or red, occasionally whitish 7

7. Stems fragile when dry or wet (i.e., detached leaves include parts of stems), rare Arctic to Arcto-alpine species 8

— Stems sturdy at least when wet (i.e., detached leaves do not include parts of stems), species with various distribution 10

8. Plants synoicous; leaves evenly colored, broadly acute, not decurrent; leaf borders partly bistratose; costae strong, subpercurrent or percurrent; capsules pyriform, symmetric with broad, short necks 0.5 the length of urns 46. B. taimyrense

This poorly known species is recognized primarily by its synoicous sexual condition and short necked capsules. However, its sporophytes are known only from the type collection which has incompletely preserved peristomes. Podpera (1954) considered Bryum taimyrense only a subspecies of Bryum pallens, but B. pallens is dioicous and has long-necked capsules.

— Plants dioicous or autoicous; without the exact above character combination 9

9. Leaves distantly spaced, not overlapping, rounded-ovate (length to width ratio ±1:1), less than 1 mm long, concave, red at base, green above; leaves unbordered 47. B. teres

A rare Arctic species known only gametophytically in Russia. It is distinguished from other Bryum species in Russia with imbricate leaves and fragile stems by its short, rounded-acute, concave leaves that are red at base; plane leaf margins; and short costae.

— Leaves closely spaced and overlapping, ovate to ovate-lanceolate (length to width ratio ± 1.5–2:1), mostly more than 1 mm long, keeled to concave, concolorous throughout; leaves bordered, borders 2–3-seriate, partly bistratose 40. B. rutilans

A mainly Arctic species occasionally found in the high mountains of the Altai. This species can be recognized by the combination of slender, dirty-green to wine-red plants; fragile stems; long-acute, concave leaves; partly bistratose leaf borders; and fairly thick-walled leaf cells. Bryum rutilans often grows in wet habitats.

10(7). Capsules red, globose, with short necks; exostome teeth obliquely striolate at places dorsally; endostome cilia short or absent; plants small (stems 0.2–0.5 cm); shoots bud-like; leaves acute, ± concave; synoicous; Arctic species 54. B. wrightii

In Russia Bryum wrightii is found in most Arctic regions as well as the Stanovoy Range of South Yakutia. Bryum wrightii is a small moss with bud-like shoots. Although it is very difficult to distinguish the gametophytes of B. wrightii from several other Bryum species, its sporophytes are distinctive in having globose capsules and strongly reduced peristomes.

— Without this exact combination of character states or sporophytes absent 11

11. Exostome teeth linear, teeth widely spaced, separated at base; delicate plants; Caucasus 14. B. caucasicum

This rare species is known only from a few, mid-elevation localities in the eastern and central Caucasus. It was previously placed in Mielichhoferia because of it strongly reduced peristome and linear, distantly spaced peristome teeth. However, no species of Mielichhoferia has such long-excurrent costae, and DNA sequence data positions the species in Bryum sensu lato.

— Exostome teeth narrowly triangular, teeth closely spaced, united at base; delicate to robust plants; not resticted to the Caucasus 12

12. Cross-walls on ventral lamellae between ventral trabeculae on lower surface of teeth numerous, forming a brick-like pattern; leaf borders unistratose; leaves red at base, green or brown above; capsules symmetric 1. B. algovicum

Bryum algovicum occurs sporadically throughout Russia. It grows on a broad range of substrates: sand, loam, clay, peat, and rocks (limestone and sandstone). The species is characterized by the combination of polyoicous sexual condition; narrow acumina; excurrent costae; leaves red at base; endostomes adherent to exostomes; and inner (ventral) surfaces of exostome teeth at base with numerous cross walls between the ventral trabeculae. This species is impossible to identify in the absence of sporophytes.

— Cross-walls on ventral lamellae between ventral trabeculae absent or rarely present, when present mostly along middle of teeth; leaf borders bistratose, leaves concolorous; capsules symmetric or asymmetric 13

13. Leaves less than 1 mm long; leaf margins plane, not bordered; shoots imbricate; leaves filiform-acuminate; tufts dense but easily disintegrated 24. B. kunzei

Bryum kunzei grows in low tufts or clusters and characteristically has closely imbricate leaves. The tufts are often whitish because its leaves have long, hyaline awns; however, its laminae are green throughout, unlike the partially colorless laminae of B. funkii and B. argenteum. The leaves of B. kunzei are rigid, concave with stout, shortly excurrent costae, and have plane to narrowly recurved, indistinctly bordered margins. Small plants of B. elegans often grow in the same habitats as B. kunzei, but they differ in having green to brown-green tufts as well as different oriented piliferous acumina. In B. elegans the acumina are reflexed to recurved from the otherwise appressed leaves; in B. kunzei the entire upper leaf is reflexed and follows the curvature of the piliferous acumina. Small, sterile collections of B. bicolor from chalk areas differ from B. kunzei in: (1) sometimes having axillary buds; (2) lacking reduced leaves on the lower parts of the stems, thus making them appear sessile; (3) having leaves that are fragile above; (4) having subdichotomous branching; and (5) less dense tufts. Bryum funkii usually has a looser growth form than B. kunzei, and never forms dense tufts. Bryum kunzei has a scattered distribution in the Russian steppe and forest zones and also occurs in the lowlands of the South Urals. It grows on sandy/rocky, open slopes on sandstone and limestone.

— Leaves more than 1 mm long; without exact combination of remaining character states 14

14. Leaf apices blunt to obtuse 15

— Leaf apices acute 22

15. Plants autoicous 16

— Plants dioicous 17

16. Exostome teeth holodontous (lacking a longitudinal furrow on ventral surface); exostome teeth reddish below, dorsal lamellae horizontally and obliquely striolate; endostomial cilia short; leaves unbordered 27. B. marratii

Bryum marratii is an autoicous species with reduced peristomes. It can be recognized in the field by its small, ellipsoidal or ovoid capsules; red exostome teeth; and obtuse or rounded acute, often ± cucullate leaves. This species is rare in Russia, known only from a few collections made in the Taimyr and Altai.

— Exostome teeth aulacodontous (with longitudinal furrow on ventral surfaces and semiperforations along median line on dorsal surfaces in proximal parts of teeth); exostome teeth yellowish below, dorsal lamellae reticulate; endostomial cilia long; leaf borders 1–2–seriate, partly bistratose 12. B. calophyllum

Bryum calophyllum is a rare Arctic species also know from the high mountains of Siberia (in Buryatia). It is autoicous and has blunt, concolorous leaves with partly bistratose borders. However, when capsules are absent it is extremely difficult to recognize without previous experience with the species. Its capsules are distinctive in having an aulacodontous peristome, i.e., exostome teeth with a longitudinal furrow on the ventral (inner) surfaces and semiperforations along median line on dorsal (outer) surfaces.

17. Leaves rounded-ovate, ovate, elliptic, or orbicular; plants hygrophytic 18

— Leaves oblong, oblong-ovate, lingulate, or lanceolate; plants mesophytic or xerophytic 20

18. Leaves red at base, green or brownish above; leaf borders 3–5-seriate, unistratose 32. B. neodamense

Arcto-alpine species with a wide distribution throughout Russia. It is similar to B. pseudotriquetrum, but different primarily in having more or less obtuse leaves, unistratose leaf borders, and non-decurrent leaves.

— Leaves concolorous; leaf borders 1–2-seriate, partly bistratose 19

19. Leaves cucullate, strongly concave; Arcto-alpine species 16. B. cryophilum

Bryum cryophilum can often be recognized in the field because it forms extensive, light vinacous-red carpets over large areas. The species is found in wet Arctic/mountain tundras, along brooks, and in fens. The presence of strongly concave leaves differentiate it from the otherwise similar B. cyclophyllum, which has lightly concave to plane leaves and grows mostly in forest zones.

— Leaf not cucullate, lightly concave or plane; widely distributed species in forest zones 17. B. cyclophyllum

This species is recognized by its roundly obtuse to orbicular leaves that are crisped when dry. In addition the leaves have plane margins, indistinct, 1–3-seriate, borders, and costae that end below the leaf apices. Plants from the Yaroslavl Province differ from typical forms of the species in having taller plants that are sometimes pinkish in color. The species occurs in cold northern regions and high mountains on wet/moist, muddy soil, and banks along lakes, ponds (often with B. pallens). In Russia this species is restricted to the forest zones.

20. Plants brownish-green to reddish, evenly colored, dull; stems to 0.5 cm, bud-like to comose; subterminal shoots thin, leaves loosely imbricate, red-colored at base 33. B. oblongum

Bryum oblongum is a rare species known in Russia from a few scattered localities in the northern parts of the boreal forest zone. It can be recognized by the combination of small red, dioicous plants; obtuse to blunt, concave leaves with red leaf bases; percurrent costae; and free endostomes that have appendiculate cilia.

— Plants variegate with some red/purple patches in different parts of otherwise green leaves, glossy; stems to 3.0 cm, evenly foliose; subterminal shoots thick, leaves imbricate 21

21. Leaf length to width ratio 2–2.4:1; exostome teeth partly striolate dorsally 31. B. muehlenbeckii

Bryum muehlenbeckii is a rare but widely distributed species known in Russia only from the Kola Peninsula, Caucasus, Altai and Kamchatka. It is a mountain species that grows on rock outcrops. When sterile Bryum muehlenbeckii and B. alpinum are easy to confuse but B. alpinum differs in having longer leaves and rhizoidal gemmae. The presence of striolate exostome teeth is a rare feature in Russian species of Bryum. It is also present in B. marratii,B. mirabile,B. purpurascens,B. wrightii, but those species differ from B. muehlenbeckii in having endostomes that are adherent to the exostome teeth.

— Leaf length to width ratio 2.8–5.5:1; exostome teeth reticulate dorsally2. B. alpinum

Bryum alpinum is mostly restricted to the Caucasus with only a scattered distribution in other regions. The presence of plants that grow in variegated tufts greatly help in recognizing the species. However, Bryum muehlenbeckii often occurs in similar variegated tufts (see discussion under that species). Bryum orientale is a little known species described from the Vladivostok area of the Russian Far East that appears to be closely related to B. alpinum, but it differs in having bordered leaves.

22(14). Rhizoidal gemmae present; bulbils in leaf axils absent 23

— Rhizoidal gemmae absent; bulbils in leaf axils present or absent 30

23. Leaves mostly broader than 0.8 mm 24

— Leaves mostly narrower than 0.8 mm 25

24. Rhizoidal gemmae red, round, pyriform or irregularly shaped, 60–80 mm in diameter; rhizoidal gemmae cells weakly convex and thick-walled; plants green, dull, stems comose; leaves concave to keeled, slightly curved when dry; leaves red at base, green above; costae long-excurrent11. B. caespiticium

Bryum caespiticium is a widespread and common species in disturbed habitats as well as dry, open, natural habitats throughout most of Russia, but rare in the northern part of Siberia. Curiously, this dioicous species often has sporophytes, and its perfect peristomes with appendiculate cilia are distinctive features of the species. It grows in dense, expanded tufts and has gradually tapered, weakly keeled leaves that are red at base, as well as leaf cells that gradually transit from short laminal to elongate border cells. The species grows mostly on soil (sand, clay or humus) in mesic to xeric, open habitats, in meadows and steppe communities, on eroded slopes, occasionally rocks, concrete, and bricks in disturbed city sites.

— Rhizoidal gemmae brownish-orange or reddish-orange, round, ca. 130 mm in diameter; rhizoidal gemmae cells weakly convex or plane and thin-walled; plants green to yellow- or brown-green, stems comose to subjulaceous, glossy or dull; leaves concave to plane, straight when dry; leaves red at base or leaves concolorous; costae percurrent to short-excurrent 28. B. mildeanum

In Russia Bryum mildeanum is found in several mountain regions. The species can be very difficult to distinguish from B. alpinum and B. turbinatum because most collections lack sporophytes as well as rhizoidal gemmae. Bryum alpinum differs in usually having conspicuously variegate plants (B. mildeanum is light-green to stramineous), and shortly acute to blunt, more strongly concave leaves. B. turbinatum differs in having leaves with clearly differentiated, usually bistratose borders. In contrast, B. mildeanum has leaves with inconspicuous to almost undifferentiated, unistratose borders.

25. Rhizoidal gemmae cells distinctly convex 26

— Rhizoidal gemmae cells plane or slightly convex 27

26. Gemmae (170–)250–280 mm, round, on rhizoids in or on soil and in leaf axils 39. B. rubens

Bryum subapiculatum is very similar to B. rubens but differs in having smaller rhizoidal gemmae (200–240 ΅m vs. (170–)250–280 ΅m), that are lighter in color (bright-red to orange-red vs. ruby-red to cherry-red), and have almost smooth rather than distinctly projecting surface cells. In addition, the gemmae in B. rubens often occur in leaf axils, whereas those of B. subapiculatum are restricted to the plant base on rhizoids in the soil. Virchenko (1989) provided good SEM illustrations of the gemmae of these two species. Bryum rubens grows on bare clay or sandy soil in open places at the edges of or within forests.

— Gemmae 60–100 mm, round to pyriform, on rhizoids in soil 22. B. klinggraeffii

Bryum klingraeffii can be recognized by its rhizoidal gemmae that are small, light-red, globose to pyriform, and composed of irregularly aggregated cells that are convex on the outer surfaces. Overall, the gemmae resemble small, imperfect raspberries. The species grows on limestone.

27. Rhizoidal gemmae 80–12055–85 ΅m, pyriform, brownish to red- to purple-brown; plants synoicous or dioicous 42. B. sauteri

This rare species is found only in the western parts of European Russia and the Caucasus. It differs from Bryum rubens and B. subapiculatum in having smaller gemmae (less than 120 mm vs. more than 150 mm). Similarly sized gemmae are also characteristic of B. klinggraeffii, but that species has bright red to purple gemmae with convex surface cells. Bryum violaceum is a difficult species to recognize because its gemmae are so variable in color. It differs from B. sauteri in having round rather than pyriform gemmae.

— Rhizoidal gemmae 60–200 ΅m in diameter, round, pale brown, brown-red, red, or violet-red; plants dioicous 28

28. Rhizoidal gemmae pale brown or violet-red, 60–110 mm; rhizoids brown to red-brown or violet; capsules dark red to red-violet 51. B. violaceum

Bryum violaceum differs from B. subapiculatum and B. rubens in having smaller gemmae. From B. klingraeffii it differs in having brownish or violet-red rather than bright red gemmae, and purple to violet setaeand capsules. Russian collections of B. violaceum have rhizoids and gemmae that lack violet pigmentation, an important diagnostic feature of the species; however, as originally described (Crundwell & Nyholm, 1963) the rhizoids in some speci­mens are sometimes pale. In addition, the only Russian collection, contrary to the descriptions of Crundwell & Nyholm (1963, 1964), Smith (1978), Savich-Ljubitskaya & Smirnova (1970), and Virchenko (1987, 1989), at times has gemmae that are not perfectly globose and have slightly convex cells. Gemmae of this type have been observed in B. ruderale Crundw. et Nyh., a species closely related to B. violaceum but differing in having larger gemmae, 125–180(–200) mm. The only specimen from European Russia is assigned to B. violaceum, mostly on the basis of gemmae size. Moreover, illustrations of B. violaceum in Crundwell & Nyholm (1964) and Virchenko (1987) show a somewhat angular surface on the gemmae. The only specimen from Russia was collected on bare peat in a peat bog.

— Rhizoidal gemmae red or brown-red, 92–200 mm; rhizoids and capsules without violet color 29

29. Rhizoidal gemmae 92–162 mm; costae long-excurrent 38. B. radiculosum

This species occurs primarily in the Caucasus, with a single record from the Kuril Islands (Iturup). All Russian collections lack sporophytes. Bryum radiculosum can be recognized on the basis of the following features: (1) green to partly reddish plants in dense tufts; (2) stems 0.2–0.3 cm long; stem tips comose to bud-like; (3) rhizoids dark-brown; (4) leaves erect when dry, 1.1–1.80.4–0.5 mm, ovate, broadest in lower 1/3, keeled-concave, acuminate, not decurrent, red at base and green above or concolorous throughout; 5) leaf margins plane to narrowly recurved; 6) leaf borders absent or indistinct, uniseriate and unistratose; 7) costae strong, long-excurrent, awn serrulate; 8) leaf cells 55–859–15 mm, thick-walled; 9) plants dioicous; 10) gemmae red to brownish red, round, cells not or slightly convex, 95–162 mm.

— Rhizoidal gemmae 150–200 mm; costae subpercurrent to short-excurrent 45. B. subapiculatum

This primarily European species is known from a few scattered localities in European Russia and the Caucasus, with a single record in the Russian Far East (Primorsky territory). Bryum violaceum and B. klinggraeffii differ from it in having smaller rhizoidal tubers (less than 120 ΅m vs. 150–200 ΅m). For distinctions between B. subapiculatum and B. rubens see comments under B. rubens.

30(22). Plants dioicous 31

— Plants synoicous, autoicous or polyoicous 43

31. At least some shoots (either stems or subterminal branches) imbricate, julaceous or bud-like; leaves distinctly concave 32

— Shoots never imbricate, julaceous or bud-like; leaves plane, keeled or only slightly concave 35

32. Plants large (stems more than 2.0 cm long), hygrophytic; leaf apices cucullate; leaf borders 4–5-seriate, partly bistratose 43. B. schleicheri var latifolium

This species forms extensive tufts of conspicuously tumid plants. When well developed the leaves of this species are the largest of any Russian Bryum species. Although typically plants of B. schleicheri var. latifolium lack sporophytes, they are distinctive in having: (1) turbinate capsules; (2) exostome teeth with about 40 plates on dorsal (outer) surfaces; (3) orange endostomes not adherent to exostome; and (4) appendiculate endostomial cilia. It is common only locally in European Russia from the Kola Peninsula to the Caucasus and in Asian Russia from Chukotka to the Primorsky Territory. Although present, it is rare in lowland areas such as West Siberia, and in Central European Russia it is known from a single locality on the banks of the upper Volga River in Tver Province.

— Plants small (stems less than 1.5 cm long), xerophytic; leaf apices plane; leaf borders 1–2-seriate, unistratose 33

33. Leaf length to width ratio 3:1; stems 0.5–1.5 cm long 28. B. mildeanum

[see couplet 24]

— Leaf length to width ratio 1.5–2:1; stems 0.3–0.5 cm long 34

34. All plants bud-like to julaceous; leaves whitish to yellowish-green; axillary bulbils absent; capsule neck narrow 20. B. funkii

This species has round- or bud-shaped plants, at times whitish leaves provide a conspicuous contrast to its cherry-red costae, and this separates B. funkii from B. argenteum, which has concolorous costae/leaf laminae. Bud-like plants of B. elegans differ from B. funkii in having green or yellow-green leaves and recurved leaf apices. Bryum dichotomum is similar to B. funkii in having concave leaves and contrastingly dark colored costae, but its leaves are erect rather than appressed. In addition, the capsule necks are broad in B. dichotomum, but narrow in B. funkii. Bryum funkii has a sporadic distribution in Russia, and has been found in most well collected, calcareous areas. It is rare in Siberia and this probably reflects a real absence rather than rarity based on undercollection.

— Female plants comose; male plants julaceous; leaves light to dark green; axillary bulbils often present; capsule neck wide 18. B. dichotomum

Bryum dichotomum has julaceous shoots that somewhat resemble those of B. kunzei, B. elegans, and B. funkii. However, those species never have axillary brood buds (bulbils), whereas these are present in most of collections of B. dichotomum. Several specimens from the steppe zone in Kursk and Voronezh Provinces (Popova, VOR) lack axillary buds and so cannot be identified with certainty, although in other features they agree with B. dichotomum. Ochi (1972) synonymized B. dichotomum (type New Zealand) and B. bicolor (type Europe) and we follow this approach. However, Demaret & Wilczek (1980) found them different, thus further studies on the variability of the B. dichotomum complex in the Southern Hemisphere are needed before a conclusive decision can be reached on whether or not the two taxa can be considered separate species. Bryum dichotomum has a scattered distribution in Russia, but is more or less common only in southern European Russia growing on wet soil, often mixed with B. pallens; in the steppe zones it grows on solid chalk outcrops.

35(31). Leaves red at base, green or brown above 36

— Leaves concolorous throughout 39

36. Leaf borders 3–5(6)-seriate, sharply delimited; plants hygrophytic 37

— Leaf borders mostly 1–2-seriate, at times broader, indistinctly delimited; plants xerophytic 38

37. Leaves ovate-lanceolate, long-decurrent; leaf apices narrowly acute; widespread species 36. B. pseudotriquetrum

Bryum pseudotriquetrum can be recognized by its tall plants and long-decurrent leaves with firm, broad leaf margins. Its differences from B. bimum are discussed under that species. A calciphilous hygrophyte, B. pseudotriquetrum is very common in boggy vegetation, secondary successions in sandy and peaty pits, at springs, along banks of rivers, creeks, streams, and lakes.

— Leaves ovate, not or shortly decurrent; leaf apices broadly acute; northern and montane species 32. B. neodamense

[see couplet 18]

38. Leaves lanceolate, concave to plane; leaf length to width ratio ca. 3:1; leaf borders 1–2-seriate, indistinctly delimited (border cells slightly longer than laminal cells) or absent; plants light-green to stramineous; capsules usually red 28. B. mildeanum

[see couplet 24]

— Leaves ovate-lanceolate, slightly concave to keeled-concave; leaf length to width ratio ca. 2:1; leaf borders 1–4-seriate, indistinctly delimited (border cells gradually transitioning to laminal cells); plants green to yellow-green; capsules brownish 11. B. caespiticium

[see couplet 24]

39(35). Capsules more or less asymmetric 40

— Capsules more or less symmetric 41

40. Leaves narrowly lanceolate to triangular, leaf length to width ratio 4–6:1 44. B. sibiricum

Bryum sibiricum is known only from Siberia. Although closely related to B. pallens, it differs in having much narrower leaves.

— Leaves ovate to ovate-lanceolate, leaf length to width ratio 1.5–2:1 34. B. pallens

This widespread Holarctic species occurs in scattered localities throughout Russia. It is fairly common in the forest regions of European Russia where it grows on sandy, loamy, clayish, silty, and peaty soils that are usually slightly calcareous. It is also found in open habitats such as river/stream banks, lake shores, inundated bogs, wet depressions in meadows, wet forest road banks, and trenches/cuvettes. The species is less common in Asian Russia, but that region is less well explored. However, by analogy with other regions with similar environmental parameters its distribution there is probably more or less continuous rather than fragmented. Bryum pallens can be recognized by its rose to wine-red colored plants, especially prominent when growing in sunny places, and long, curved capsules. Additional noteworthy features of B. pallens include: (1) concolorous leaves; (2) dioicous sexual condition; (3) endostomes free; (4) endostomial cilia variable in length, 1/2–7/8 endostome length, nodose or appendiculate. Because B. pallens is so widespread geographically and has such broad ecological amplitude it can be difficult to distinguish from B. altaicum and B. uliginosum. Although these two species are superficially similar to B. pallens, both have endostomial basal membranes adherent at base to the exostome teeth. In addition, B. uliginosum is autoicous and has cilia either very short or absent, while B. altaicum is synoicous, and has well-developed appendiculate endostomial cilia.

41. Capsules pyriform, leaf length to width ratio 2.5–4:1; leaf borders unistratose; plants xerophytic 28. B. mildeanum

— Capsules turbinate, leaf length to width ratio 1.5–3:1; leaf borders bistratose; plants hygrophytic 42

42. Leaf length to width ratio 1.5–2:1; leaf borders 3–4(–5)-seriate 43. B. schleicheri

Bryum schleicheri is similar to very robust plants of B. turbinatum, but differs from it in having broader leaves (length to width ratio 1.5–2:1 vs. 3:1) and broader leaf borders (3–4(–5)-seriate vs. (1–2(–3)-seriate). Bryum schleicheri var. latifolium is a more widespread variety of the species (see couplet 32).

— Leaf length to width ratio 3:1; leaf borders 1–2(–3)-seriate 49. B. turbinatum

Collections of this polymorphous species seldom have sporophytes. When growing in sunny habitats, B. turbinatum forms low (1–2 cm high) dirty olive-green to pinkish tufts similar in color to B. pallens. But it is distinguished from B. pallens by its weakly bordered (1–2(–3)-seriate) leaves. In contrast the leaf borders in B. pallens are always clearly defined and bistratose. Plants of B. turbinatum from shady habitats are taller (2–3(–4) cm high), paler, and often resemble weak phenotypes of B. pseudotriquetrum. These large plants of B. turbinatum can be recognized by their non-decurrent leaves that are more weakly bordered (2–3–seriate vs. 3–5(–6)-seriate). When sporophytes are present, the pyriform or turbinate capsules that are relatively short and strongly contracted below the mouth are diagnostic features of the species. Bryum turbinatum grows on wet/moist, sandy to clayish soil, sometimes among loose herbaceous vegetation; in wet meadows, river banks, along streams, edges of mires, at springs, and on partly submerged sandstone.

43(30). Plants autoicous 44

— Plants synoicous or polyoicous 48

44. Endostome free; endostomial cilia long 35. B. pallescens

Bryum pallescens is often thought to be more widespread than as treated here, because it includes polyoicous plants that are considered here a separate species, B. lonchocaulon (cf. Zolotov, 2000). As treated here, B. pallescens is a rare Russian species known from only a few collections in north-western European Russia, the Ural Mountains, the Caucasus and Siberia. Bryum pallescens can be recognized by the following features: (1) cladoautoicous sexual condition; (2) broad, (3)4–5(6)-seriate, but unclearly defined, unistratose borders; (3) evenly foliate subterminal shoots; (4) red leaf bases (5) free endostomes; (6) long, appendiculate cilia.

— Endostome adherent to exostome; endostomial cilia short 45

45. Exostome teeth aulacodontous (with longitudinal furrow on ventral (inner) surfaces); subterminal shoots thin, loosely foliate with small leaves; opercula small to large, nearly plane 8. B. axel-blyttii

This species occurs in the mountains of northern Siberia, in European Russia in the Kola Peninsula and Arctic regions. Bryum axel-blyttii is characterized by the following combination of features: (1) shortly pyriform, narrow necked capsules; (2) exostome teeth with longitudinal furrows on ventral (inner) surfaces, but without perforations along the median lines; (3) endostomial basal membranes fused to exostome teeth; (4) short endostomial cilia; (5) cladoautoicous sexual condition (perigonia on short branches below perichaetia); (6) partly bistratose leaf borders; (7) leaves concolorous throughout; (8) acute leaves; (9) and subterminal shoots with loosely arranged leaves. The closely related B. calophyllum differs from B. axel-blyttii in having numerous perforations along the median lines of the exostome teeth and blunt leaves. However, in the absence of sporophytes the two species can not be reliably distinguished.

— Exostome teeth holodontous (without longitudinal furrow on ventral (inner) surfaces); subterminal shoots comose or evenly imbricate, with somewhat smaller leaves; opercula small, convex 46

46. Septae between ventral trabeculae of exostome teeth absent or solitary; capsules asymmetric 50. B. uliginosum

This species is somewhat widespread, known from the Holarctic, different parts of Russia, as well as others places in the world, but nowhere is it very common. It grows on wet, clayish soil in open habitats. The species can be distinguished by the following combination of features: (1) long, curved capsules with oblique mouths; (2) endostomial basal membranes adherent to the exostome; (3) short, narrow endostomial cilia; (4) narrowly perforated endostomial segments; and (5) autoicous sexual condition. The gametophytes of B. uliginosum are similar to those of B. pallens,but they have larger upper leaves, that may be 5–6 mm long. In contrast the upper leaves of B. pallens are 1.2–3.1 mm long. In addition, B. ulignosum has longer leaf cells than B. pallens (80–200 ΅m vs. 60–80 ΅m long). Finally, B. uliginosum is autoicous while B. pallens is dioicous. The distinctions between B. uliginosum and B. altaicum are discussed under that species.

— Septae between ventral trabeculae of exostome teeth numerous; capsules symmetric 47

47. Capsules shortly pyriform, length to width ratio 2:1 52. B. warneum

This rare species is known in Russia only from the Komi Republic, Altai and Yakutia. It grows on wet soil, and can be recognized by the following combination of features: (1) autoicous sexual condition; (2) broadly acute, subentire leaf apices; (3) leaf bases not red; (4) endostome adherent to exostome teeth; (5) endostomial cilia reduced; and (6) exostome teeth with numerous septae between ventral trabeculae along the median lines. Bryum algovicum is similar to B. warneum but differs in having synoicous or polyoicous plants and exostome teeth with more septae between the ventral trabeculae that are not only arranged along the median lines (B. warneum has most septae arranged along the median lines, excepting for the lowermost 2–3 trabeculae where septae are often more numerous). When sporophytes are absent B. warneum can not reliably be identified.

— Capsules pyriform, length to width ratio 3–3.5:1 10. B. bryoides

Known in Russia only from the Kola Peninsula and Altai. Bryum bryoides can be identified by the following combination of features: (1) exostome teeth with numerous septae between ventral trabeculae along median lines; (2) endostomial basal membrane adherent to exostome teeth; (3) endostomial cilia reduced; (4) pyriform capsules with length to width ratio 3–3.5:1; (5) autoicous sexual condition; (6) leaves concolorous throughout; (7) leaf borders bistratose. Bryum bryoides can be difficult to separate from B. arcticum and B. warneum. However B. arcticum has curved capsules and synoicous, often deeply red colored plants. Bryum warneum differs in having shorter capsules (length to width ratio ca. 2:1).

48(43). Perisome aulacodontous 49

— Peristome holodontous 51

49. Endostome not adherent to exostome; cilia long, appendiculate; spores 12–16(–22) mm 15. B. creberrimum

This is one of the most common Bryum species in Russia, its differences from B. pallescens, B. bimum, and B. lonchocaulon are discussed under those species. Bryum creberrimum grows on wet/moist soil, peat, eroded chalk, limestone mixed with humus, and rarely on rotten wood in swamps, meadows, meadow-steppes, and secondary vegetation.

— Endostomial basal membrane adherent to exostome; cilia short; spores 24–42 mm 50

50. Plants 0.2–0.5 cm high; leaf borders 1–2–seriate, weakly defined; spores ferrugi5. naceous to brown or reddish, coarsely papillose 5. B. archangelicum

This mainly northern and high mountain species has a scattered distribution in Russia. Bryum archangelicum is characterized by: (1) exostome teeth aulacodontous (with longitudinal furrow on ventral (inner) surfaces along median lines); (2) acuminate leaves with long-excurrent costae; (3) red leaf bases; (4) 1–2-seriate leaf border that are indistinctly defined; (5) polyoicous sexual condition; (6) endostomial basal membrane adherent to exostome teeth; (7) endostomial cilia short; and (8) small plants less than 0.5 cm high.

— Plants 0.5–1.0 cm high; leaf borders (2–)3–5-seriate, sharply defined; spores olive to brown, finely papillose 41. B. salinum

This species grows on soil and rock along the sea coasts in north-west European Russia and the Russian Far East. In addition, it occurs in some northern, interior areas and occasionally in other regions, such as Orenburg Province. Bryum salinum has the following combination of diagnostic features: (1) exostome teeth aulacodontous (with longitudinal furrow on ventral (inner) surfaces along median lines and single perforations at teeth bases; (2) polyoicous sexual condition; (3) endostomial basal membrane adherent to exostome teeth; (4) endostomial cilia short; (5) leaves with broad, unistratose borders; and (5) red leaf bases. A form with larger spores 28–36(–42) mm vs 22–30 mm and more numerous perforations in exostome teeth, known as Bryum lapponicum Kaurin nom. illeg., may represent a separate species.

51(48). Spores 40–50 mm 26. B. longisetum

This rare species is known from only single localities in European and Asian Russia. It grows on rocks/soil and occasionally in more or less saline areas in the steppe zone. Bryum longisetum differs from all other Russian species of Bryum by its large spores (40–50 ΅m); usually very long setae (to 5 cm long); leaves red at base, leaf borders unistratose and broad (to 5-seriate), synoicous or polyoicous sexual condition, endostomial basal membrane adherent to exostome teeth, and endostomial cilia short.

— Spores less than 40 mm 52

52. Exostome teeth stiolate on dorsal (outer) surface 53

— Exostome teeth reticulate on dorsal (outer) surface 54

53. Stems to 1 cm long; rhizoids restricted to stem bases; capsules oblong-pyriform to oblong-ovate (length to width ratio 2:1) 37. B. purpurascens

Although this species has been reported from many areas in Russia, a revision of herbarium material indicates that it occurs only in the northernmost regions of European Russia and West Siberia. The species is characterized by the following combination of features: (1) leaf borders bistratose; (2) synξicous sexual condition; (3) exostome teeth striolate on dorsal (outer) surfaces; (4) septae between ventral trabeculae absent; (5) endostomial basal membrane adherent to exostome teeth; (6) endostomes with cilia ca. half segment length. In the absence of sporophytes this species can not be reliably identified.

— Stems to 3 cm long; rhizoids extending to upper leaves; capsules short pyriform (length to width ratio 1.5:1) 29. B. mirabile

This species was described from and is only known from Chukotka. Bryum mirabile is characterized by long, evenly imbricate, ovate to elliptic leaves; shortly acute leaf apices with attenuate reflexed apiculi; bi- or multistratose leaf margins; exostome teeth striolate on dorsal (outer) surfaces; endostome adherent to exostome teeth; low endostomial basal membranes (1/3 endostome height); and fairly large spores (32–40 mm).

54. Endostomial ciliae long, appendiculate 55

— Endostomial ciliae short, rudimentary or nodose 59

55. Endostome adherent to exostome; leaf borders bistratose; leaves concolorous throughout 3. B. altaicum

Bryum altaicum is known from scattered localities in Siberia and northern European Russia. It can be recognized by the following combination of features: (1) elliptic leaves with bistratose borders; (2) curved capsules; (3) holodontous peristomes (i.e., lacking a longitudinal furrow on ventral (inner) surface); (5) synoicous sexual condition; (6) endostomial basal membranes adherent to exostomes; (7) long-appendiculate endostomial cilia. Bryum uliginosum is similar to B. altaicum, but differs in having short to rudimentary endostomial cilia and autoicous plants. In the absence of sporophytes B. altaicum can not be reliably identified.

— Endostomes free; leaf borders unistratose; leaves red at base, green or brownish above 57

56. Capsules asymmetric, somewhat gibbous; endostomial cilia nodose or rarely shortly appendiculate; spores 24–32 mm 21. B. intermedium

In the absence of sporophytes B. intermedium can not be reliably identified. The following sporophytic features are important in distinguishing this species: (1) asymmetric capsules with long, persistent opercula; (2) long, nodose to very shortly appendiculate endostomial cilia; (3) endostomes not adherent to exostomes; and (4) large spores that are variable in size but mostly ca. 25 mm. In addition, this species is synoicous and has indistinct leaf borders. Bryum intermedium grows on fine soil over gypsum, limestone and sandstone outcrops.

— Capsules symmetric or weakly asymmetric, not gibbous; endostomial cilia appendiculate; spores less than 24 mm 57

57. Plants polyoicous with perigonia on subterminal shoots 25. B. lonchocaulon

Bryum lonchocaulon is similar to B. pallescens and B. creberrimum. For a discussion of the differences between these species see B. pallescens. Bryum lonchocaulon is found in the Russian forest and steppe zones often on dry slopes, in synantropic vegetation, and sometimes in wet swamping and flooded meadows. It grows on soil (sand, clay, peat), rocks, and old brick walls

— Plants synoicous 58

58. Leaf median cell walls 1.5 mm thick; leaf borders 2–3(–4)-seriate; costae long-excurrent; leaf apices acuminate 15. B. creberrimum

[see Couplet 49]

— Leaf median cell walls 2–2.5 mm thick; leaf borders 4–6-seriate; costae percurrent to short-excurrent; leaf apices acute 9. B. bimum

Bryum bimum is often considered an infraspecific unit or synonym of B. pseudotriquetrum, and as a result it is difficult to know its precise distribution. It is broadly distributed across the Holarctic region and apparently has a bipolor distribution. In Russia it is known from all areas that have been sufficiently studied, except the xeric regions. It grows on calcareous substrates in mesic/wet places, including meadows, various mires, fens, swamps, and irrigational channels. Occasionally it is found on silty river banks and brick walls. In the steppe zone it has been collected on chalk outcrops in more or less wet conditions. Bryum bimum is especially similar to B. creberrimum. However, B. bimum is a more hygrophylous species than B. creberrimum, occurring in a wider range of habitats. When found in the same habitats, B. bimum differs from B. creberrimum in having plants that grow in high tufts and leaves with longer decurrencies. In addition, B. bimum differs from B. creberrimum in the following features: (1) thicker cell walls (2–2.5 vs. ca. 1.5 ΅m wide); (2) broader leaf borders (4–6-seriate vs. 2–3(–4)-seriate); and (3) costae excurrent into a shorter awn. Bryum pseudotriquetrum differs from B. bimum in its sexual condition (dioicous vs. synoicous); leaf apices more gradually tapered; and thinner, less incrassate leaf cell walls (1.0–1.5 vs. 2–2.5 ΅m).

59(54). Exostome teeth usually with septae between ventral (inner) trabeculae, mostly along tooth median, often one above another; leaf borders partly bistratose 6. B. arcticum

This Arctic and permafrost zone species grows on soil and is especially common in calcareous areas. The species is characterized by the following combinations of features: (1) exostome teeth with septae between the ventral trabeculae, one per lamellae plate thus dividing them in half; (2) dorsal (outer) surfaces of exostome teeth with reticulate ornamentation; (3) partly bistratose leaf borders; (4) curved, asymmetric capsules; (5) synoicous sexual condition; (5) leaves concolorous throughout; and (6) plants pinkish to red. Bryum warneum differs from B. arcticum in having symmetric capsules; usually an autoicous sexual condition; and consistently green colored plants. Bryum purpurascens differs from B. arcticum in having exostome teeth that are striolate on the dorsal (outer) surfaces and septae absent or very few between the ventral trabeculae of the exostome teeth. The distinctions between B. arcticum and B. bryoides are discussed under B. bryoides. In the absence of sporophytes this species can not be reliably identified.

— Exostome teeth without or rarely with septae between ventral (inner) trabeculae; leaf borders unistratose 60

60. Subterminal shoots comose; leaves slightly concave; costae long-excurrent; endostomial basal membrane 1/3–1/2 endostome length 4. B. amblyodon

This bipolar species has a broad distribution throughout Russia, especially in the northern and mountain areas. In lowland regions it has a more scattered distribution and occurs in wet open places on peaty and clayish soil. In order to reliably identify B. amblydon both sporophytic and gametophytic characters must be examined. Bryum amblyodon differs from B. archangelicum in peristome type (holodontous vs. aulacodontous); spore color (yellow- to brown-green vs. brown-ferrugineous to orange or reddish); and leaf border development (broad, sharply delimited, 2–6-seriate vs. narrow, indistinctly delimited, 1–2-seriate). In the absence of sporophytes this species can not be reliably identified.

— Subterminal shoots mostly evenly imbricate; leaves concave; costae percurrent or short-excurrent; endostomial basal membrane 1/4 endostome length 23. B. knowltonii

This circum-holarctic species has a scattered distribution in the northern regions of Asian and European Russia. It grows in wet, open, soil habitats, especially near streams, lakes, and rivers. Bryum knowltonii can be recognized by the following combination of features: (1) low endostomial basal membranes, not exceeding 1/4 endostome length; (2) endostomial basal membranes adherent to exostomes; (3) endostomial cilia short; (4) imbricate subterminal shoots; (5) unistratose leaf borders; and (6) synoicous or polyoicous sexual condition. Bryum knowltonii and B. amblyodon have similar peristomial features. However B. knowltonii differs from B. amblyodon in subterminal shoot form (imbricate vs. comose); leaf stance (concave vs. slightly concave); costa development (subpercurrent to percurrent vs. distinctly excurrent); and endostomial basal membrane height (1/4 vs.1/3–1/2 endostome length). In the absence of sporophytes this species can not be reliably identified.