2. Pinnatella M. Fleisch.   羽枝藓属   yu zhi xian shu

Hedwigia 45: 79. 1906.

 

Plants medium-sized to rather large, rarely small, yellowish green or dark green, not glossy, in loose tufts or mats. Primary stems creeping; secondary stems erect or ascending, to 10 cm long, 1–2-pinnately branched; pseudoparaphyllia foliose; central strand well differentiated or absent. Stipe leaves triangular to broadly ovate; stem and branch leaves similar, mostly ovate or oblong-ovate, rarely broadly lingulate, usually strongly concave, sometimes transversely undulate, obtuse, broadly acute, or shortly acuminate at the apex; margins serrate above; costae single, ending near leaf apex, rarely shorter and double; upper leaf cells usually rounded-quadrate, rounded-hexagonal, rhombic, or elliptical, moderately thick-walled, sometimes papillose; median cells slightly elongate; basal cells rectangular to oblong, somewhat thick-walled, sometimes porose; alar cells few, quadrate to shortly rectangular; intramarginal cells below the mid-leaf more or less differentiated. Axillary hairs 3–5 cells long. Dioicous. Perichaetia laterally on secondary stems. Setae short, straight, smooth or scabrose; capsules ovoid to oblong-ovoid, erect to slightly inclined, symmetric; opercula conic, obliquely rostrate; annuli not differentiated; peristome double; exostome teeth 16, lanceolate, densely papillose, often perforate; endostome segments narrowly lanceolate, slightly shorter or as long as the teeth, densely papillose; basal membrane moderately high; cilia absent. Calyptrae cucullate, grayish brown, sparsely hairy. Spores spherical, finely papillose.

 

1. Leaves strongly complanate, shortly wide-spathulate, often lobed at the base; costae nearly absent................

1. Leaves often concave, mostly ovate or oblong-ovate, rarely broadly lingulate, not lobed at the base; costae usually single, strong, or sometimes short............................................................................................................. 2

2. Intramarginal cells (teniolae) below the leaf apex clearly and strongly differentiated.. 1. P. alopecuroides

2. Intramarginal cells below the leaf apex not or weakly differentiated.............................................................. 3

3. Leaf apices narrowly acute or acute....................................................................................................................... 4

3. Leaf apices obtuse or obtusely acute..................................................................................................................... 6

4. Plants to 20 cm long; leaves ovate-lanceolate, narrowly acute at the apex; median leaf cells 15–25 µm × 4–5 µm, distinctly elongate, longer than upper cells 12–20 µm × 5–6 µm......................... 9. P. taiwanensis 

4. Plants only to 10 cm long; leaves broadly ovate-lanceolate or nearly triangularly ovate-lanceolate, shortly acute at the apex; median and upper leaf cells more or less similar, 6–15 µm × 5–10 µm........................... 5

5. Central strand present in stem cross section................................................................................... 2. P. ambigua

5. Central strand absent in stem cross section...................................................................................... 7. P. makinoi

6. Costae single, slender, reaching just above the mid-leaf or sometimes shorter, double; median leaf cells sublinear, 20–30 µm long, thick-walled, distinctly porose............................................ 3. P. anacamptolepis

6. Costae single, thick, reaching to the leaf apex, occasionally costae forked at the tips; median leaf cells oval to rhomboidal, 10–20 µm long, moderately thick-walled, not or indistinctly porose............................ 7

7. Central strand present in stem cross section; leaves oblong-ovate............................................. 6. P. kuehliana

7. Central strand absent in stem cross section; leaves ovate-lingulate.................................................................... 8

8. Stipe leaves triangular; stem leaves 2.5–2.6 mm × 1.2–1.3 mm, distinctly undulate or plicate when dry, moderately decurrent at the base................................................................................................ 4. P. foreauana

8. Stipe leaves ovate; stem leaves 1.5–2.2 mm × 0.8–0.9 mm, somewhat plicate when dry, not decurrent at the base.............................................................................................................................................. 8. P. robusta