4. Homaliodendron M. Fleisch.   树平藓属   shu ping xian shu

Hedwigia 45: 72. 1906.

 

Plants usually medium-sized to rather large, sometimes small, yellow to brownish green, somewhat to strongly glossy, often complanately frondose, in loosely gregarious or pendulous mats. Primary stems creeping, leaves deciduous, or with scale-like leaves and reddish brown rhizoids; secondary stems dendroid, often 1–3-pinnately branched, sometimes with flagelliform branches; rounded or oval in cross section, cortical layers consisting of small, thick-walled cells and enlarged, hyaline medullary cells; a central strand absent. Stem leaves complanately appressed, ovate, oblong-ovate, or lingulate, rarely broadly ovate with the upper part wider than the lower, acute, obtuse to rounded at the apex; margins entire below, crenulate, serrulate to irregularly toothed at the apex; costae single, often strong, reaching beyond mid-leaf, sometimes shorter, forked; branch and branchlet leaves somewhat dimorphic, broadly obovate, oblong-ovate to oblong or narrowly lingulate; upper and median leaf cells rounded-quadrate or elongate-rhombic to shortly rhomboidal, more or less thick-walled; basal cells narrowly rectangular, thick-walled, porose. Dioicous. Perigonia and perichaetia on secondary stems and main branches. Perigonial leaves ovate, concave. Inner perichaetial leaves sheathing at the base, lanceolate above. Setae short, straight, light yellow, smooth; capsules ovoid to oblong-ovoid, shortly exserted; opercula conic, with a short beak, smooth; peristome double; exostome teeth lanceolate, finely papillose, striolate below on outer surface, trabeculate on inner surface; endostome segments linear, keeled, perforate; basal membrane low; cilia absent. Calyptrae cucullate, often hairy, rarely smooth. Spores spherical, roughened or finely papillose.

 

1. Leaves broadly oblong-lingulate or spathulate, rounded-obtuse at the apex; leaf margins crenulate at the apex................................................................................................................................................................................ 2

1. Leaves oblong-ovate, ovate-lingulate, or lingulate, often acute or narrowly obtuse at the apex; leaf margins irregularly coarsely dentate..................................................................................................................................... 3

2. Plants small, usually 1–2 cm long, simple or 1–2-pinnately branched, flagelliform branches often present; median leaf cells ca. 15 µm × ca. 7 µm......................................................................................... 2. H. exiguum

2. Plants rather large, to 10 cm long or longer, 2–3-pinnately branched; flagelliform branches rare; median leaf cells 25–35 µm × 6–7 µm............................................................................................. 5. H. microdendron

3. Leaves usually short and broad, obtuse at the apex.................................................................... 3. H. flabellatum

3. Leaves usually elongate, oblong-ovate, often acute, sometimes rounded-obtuse at the apex........................... 4

4. Leaf cells papillose................................................................................................................... 7. H. papillosum

4. Leaf cells smooth................................................................................................................................................. 5

5. Leaf apices rounded-obtuse at the apex............................................................................... 6. H. montagneanum

5. Leaf apices acute or narrowly obtuse at the apex.................................................................................................. 6

6. Costae thick, mostly reaching just below leaf apex.......................................................... 1. H. crassinervium

6. Costae thin, usually vanishing above mid-leaf................................................................................................... 7

7. Leaves nearly similar in width throughout, acute or narrowly obtuse at the apex............... 4. H. ligulaefolium

7. Leaves usually narrowed at the base, acute at the apex........................................................ 8. H. scalpellifolium