Dicranum in Moss Flora of China @ efloras.org

17. Dicranum Hedw., Sp. Musc. Frond. 126. 1801.

曲尾藓属

Plants small to large or robust, green to yellowish green or golden brown, mostly shiny, in densely tomentose tufts. Stems erect, simple or branched; central strand present. Leaves usually falcate-secund, sometimes crispate when dry, narrowly lanceolate to ovate-lanceolate, gradually to rather abruptly narrowed to a keeled or subtubulose acumen; smooth or papillose at back; margins entire to serrate, not bordered, usually unistratose, occasionally bistratose at the margins; costa narrow, subpercurrent to shortly excurrent, smooth or with serrate ridges at back, with dorsal and ventral stereid bands in transverse section; cells subquadrate to elongate, thick-walled, porose or non-porose; alar cells well developed, often inflated, unistratose or bistratose, rarely multi-stratose, yellowish brown or hyaline. Dioicous. Male plants sometimes dwarfed and attached to the tomentum of the female plants. Perichaetial leaves convolute-sheathing at base, abruptly narrowed to a linear and subulate acumen. Setae elongate, straight, single or aggregate, yellowish to reddish; capsules usually cylindric, erect to inclined, or horizontal, symmetric, or curved and asymmetric, furrowed or not furrowed when dry, not or occasionally slightly strumose at base; opercula long-rostrate; annuli absent or present; stomata present; peristome teeth 16, lanceolate, reddish brown, divided to the middle or lower, sometimes divided into 3 unequal segments, vertically pitted-striolate below, papillose at the pale tips. Calyptrae cucullate, smooth, entire at base. Spores spherical, faintly papillose to coarsely papillose.

C. Gao (1994) reported 43 species and one subspecies of Dicranum from China. P.-C. Chen et al. (1963) and C. Gao (1994) recognized three subgenera under Dicranum, subg. Crassidicranum Limpr., subg. Dicranum Mitt., and subg. Pseudochorisodontium Broth. In this treatment the subgenus Pseudochorisodontium is redefined and elevated to generic rank, including six Chinese species. Dicranum here consists of twenty-nine species.

1 Leaves bistratose above; alar cells usually unistratose; capsules erect or slightly curved; plants usually brownish green (2)

+ Leaves unistratose above or sometimes thickened here and there at the margins; alar cells usually bi- to multi-stratose; capsules often curved; plants usually green to bright green (8)

2 (1) Plants with flagelliform branchlets in the axils of upper leaves 19 Dicranum mayrii

+ Plants without flagelliform branchlets (3)

3 (2) Leaves fragile or rigid, easily broken off in the upper part (4)

+ Leaves not fragile or rigid (5)

4 (3) Plants larger, 2-5 cm high; costa broader, occupying 1/3 or more of the total leaf base width; lower leaf cells usually quadrate 8 Dicranum fulvum

+ Plants smaller, less than 2 cm high; costa narrower, occupying less than 1/3 the leaf base width; lower leaf cells usually short-rectangular 29 Dicranum viride

5 (3) Upper leaf cells and costa serrate or papillose on the dorsal surface (6)

+ Upper leaf cells and costa smooth on the dorsal surface (7)

6 (5) Peristome teeth densely papillose throughout 22 Dicranum papillidens

+ Peristome teeth smooth above, faintly vertically striate below 15 Dicranum leiodontium

7 (5) Costa percurrent, without hairpoint 11 Dicranum hamulosum

+ Costa excurrent, ending in a long setaceous point 3 Dicranum cheoi

8 (1) Leaves narrowly lanceolate, erect, rigid; leaf margins entire or nearly so; boundaries between the basal cells and alar cells indistinct (9)

+ Leaves lanceolate or lance-lingulate, falcate-secund, soft; leaf margins serrulate; boundaries between the basal cells and alar cells distinct (13)

9 (8) Costa excurrent, ending in a long hairpoint (10)

+ Costa percurrent to shortly excurrent, but not ending in a hairpoint (11)

10 (9) Leaves fragile, easily broken off in the upper part when dry 7 Dicranum fragilifolium

+ Leaves not fragile, sometimes broken off when dry, but not conspicuously deciduous 25 Dicranum setifolium

11 (9) Capsules suberect to inclined, oblong-ovoid, not curved when dry and empty 12 Dicranum himalayanum

+ Capsules erect, cylindric, becoming curved when dry and empty (12)

12 (11) Leaves ending in an acute apex with a sharp-pointed tip 6 Dicranum elongatum

+ Leaves ending in a blunt apex without a sharp-pointed tip 10 Dicranum groenlandicum

13 (8) Upper leaf cells quadrate to short-rectangular or rounded quadrate to oval (14)

+ Upper leaf cells elongate-rectangular to linear or oblong-oval (20)

14 (13) Leaf margins bistratose, double-teethed (15)

+ Leaf margins unistratose, single-toothed (18)

15 (14) Alar cells multi-stratose (3-5 layered) (16)

+ Alar cells uni- to bistratose (1-2 layered) (17)

16 (15) Leaves strongly undulate above; costa stout 5 Dicranum drummondii

+ Leaves not undulate above; costa slender 4 Dicranum crispifolium

17 (15) Capsules suberect, not strumose at base, scarcely furrowed when dry and empty; inner perichaetial leaves with a long hairpoint; male plants dwarfed 20 Dicranum muehlenbeckii

+ Capsules inclined to horizontal, slightly strumose at base, usually furrowed when dry and empty; inner perichaetial leaves with a short hairpoint; male plants normal 9 Dicranum fuscescens

18 (14) Leaves narrowly lanceolate, distinctly undulate above, with a long, setaceous apex 28 Dicranum undulatum

+ Leaves ovate-lanceolate, not unduate above, with a short, narrowly acuminate apex (19)

19 (18) Upper leaf cells quadrate, papillose on the dorsal surface 26 Dicranum spurium

+ Upper leaf cells oval, smooth on the dorsal surface 16 Dicranum linzianum

20 (13) Leaves strongly undulate 23 Dicranum polysetum

+ Leaves not or occasionally slightly undulate (21)

21 (20) Costa percurrent; leaf apex obtuse or shortly acute (22)

+ Costa excurrent; leaf apex narrowly acuminate to long-setaceous point (25)

22 (21) Alar cells bi- to tristratose; costa with 2 rows of lamella-like regular teeth on the upper dorsal surface 24 Dicranum scoparium

+ Alar cells unistratose; costa irregularly serrate on the upper dorsal surface (23)

23 (22) Plants dark green; leaves short, 5-7 mm long, very soft, densely serrate at the apex 21 Dicranum nipponense

+ Plants green to brownish green; leaves generally more than 7 mm long, rigid or not particularly soft, irregularly serrate or distantly serrulate at the apex (24)

24 (23) Leaves lanceolate, narrowly acuminate, distinctly serrulate or subentire at the apex; plants slender 27 Dicranum subporodictyon

+ Leaves lance-lingulate, narrowly obtuse, irregularly serrate at the apex; plants robust 2 Dicranum bonjeanii

25 (21) Upper leaf margins double-toothed 18 Dicranum majus

+ Upper leaf margins single-toothed (26)

26 (25) Alar cells multistratose (3-4 layered) 1 Dicranum assamicum

+ Alar cells uni- to bistratose (27)

27 (26) Alar cells unistratose 14 Dicranum kashmirense

+ Alar cells bistratose (28)

28 (27) Capsules inclined to horizontal; setae 3-6 cm long; spores coarsely papillose; male plants dwarfed 13 Dicranum japonicum

+ Capsules erect to suberect; setae up to 3 cm long; spores minutely papillose; male plants not dwarfed 17 Dicranum lorifolium

List of lower taxa