AMBLYSTEGIACEAE

柳叶藓科 liu ye xian ke

by Wu Yu-Huan, Gao Chien, and Li Wei

Plants slender to somewhat robust, dull or slightly glossy, flaccid, forming loosely or densely caespitose tufts. Stems erect or ascending, rarely creeping, irregularly branched or irregularly pinnately branched; paraphyllia usually absent, if present, filiform or foliose; pseudoparaphyllia usually present. Rhizoids usually smooth, rarely papillose. Stem and branch leaves more or less similar, erect or falcate-secund, broadly elliptic or ovate at base, sometimes more or less decurrent at base, lanceolate above, round-obtuse, abruptly or gradually acuminate; margins entire or slightly serrulate; costae usually single, sometimes forked or double, very short or entirely absent; median leaf cells broadly rectangular, hexagonal, rhomboidal or linear-vermiform, generally smooth, rarely papillose or prorate; basal leaf cells wider and shorter, usually thick-walled or porose; alar cells usually distinctly differentiated. Autoicous or dioicous. Perichaetia and perigonia usually developed from tips of stems; inner perichaetial erect, elongate-lanceolate, sometimes plicate; costae single or absent, rarely forked. Setae elongate, reddish or reddish brown, smooth; capsules cylindrical or ellipsoidal, suberect or inclined, sometimes dorsally arching curved, constricted below mouth when dry or after dissemination of spores; exothecial cells rectangular or hexagonal, round or quadrate, thin-walled or thick-walled; opercula conical at base, rostrate at tips; exostome teeth cross-striate at base, papillose above, inner surface trabeculate; endostome segments, usually split; basal membrane high; cilia developed, usually long, 1–4, nodulose. Calyptrae cucullate, smooth. Spores small, spherical, often papillose.

1. Leaves bordered by 2–5 rows of linear cells................ 17. Sciaromiopsis

1. Leaves not bordered................................................................................................2

2. Stems with dense paraphyllia............................................................3

2. Stems without paraphyllia, often with pseudoparaphyllia.................... 4

3. Alar cells differentiated, inflated in well-marked groups.... 8. Cratoneuron

3. Alar cells not differentiated..............................................16. Sasaokaea

4. Plants usually robust, 10–20 cm long, pinnately or subpinnately branched................................................ 5

4. Plants delicate, 0.5–5 cm long, rarely larger, slender, up to 15 cm long, irregularly branched.................. 11

5. Leaves strongly falcate-secund, acuminate at apex; costae single.......... 6

5. Leaves straight or somewhat falcate-secund, obtuse to shortly apiculate, rarely acuminate at apex; costae single, double, or absent......................8

6. Plants in dried terrestrial habitats; pseudoparaphyllia numerous; capsules cylindrical, sometimes erect; cilia 1–3....................15. Sanionia

6. Plants aquatic or amphibious, often submerged; pseudoparaphyllia few; capsules oblong to cylindrical, always arcuate; cilia 2–3....................7

7. Leaf margins entire above..........................................9. Drepanocladus

7. Leaf margins serrulate above.....................................19. Warnstorfia

8. Costae single..............................................................................9

8. Costae double, short or indistinct.................................................10

9. Leaf apices shortly apiculate..............................................2. Callialaria

9. Leaf apices obtuse............................................................3. Calliergon

10. Alar cells differentiated, in a well-marked group, inflated...4. Calliergonella

10. Alar cells not or only weakly differentiated................. 18. Scorpidium

11. Pseudoparaphyllia usually foliose, sometimes few or absent; leaf apices obtuse; apical leaf cells shorter than median cells.........11. Hygrohypnum

11. Pseudoparaphyllia filamentous or foliose; leaf apices acute; apical leaf cells longer than median cells............................................... 12

12. Stem leaves erect to somewhat spreading; median leaf cells shortly rhomboidal................................................................................. 13

12. Stem leaves widely spreading to squarrose; median leaf cells elongate-rhomboidal................................................................................. 16

13. Plants delicate, 1.0–1.5 cm long; stems without a central strand; cilia usually single........................................................ 14. Platydictya

13. Plants medium-sized to robust, 2–5 cm (to 15 cm) long; stems with a central strand; cilia 1–3............................................................ 14

14. Plants rather robust; pseudoparaphyllia filamentous to foliose; median leaf cells 50–120 µm long, rather thin-walled; alar cells few, rectangular......................... 13. Leptodictyum

14. Plants small to medium-sized; pseudoparaphyllia foliose; median leaf cells 20–50 µm long, moderately thick-walled; alar cells numerous, often oblate or rectangular............................................................ 15

15. Costae strong, ending below the apex or often percurrent; median leaf cells oblong-rhombic........................................ 10. Hygroamblystegium

15. Costae slender, just above the mid-leaf or rarely percurrent; median leaf cells elongate-rectangular or long-rhomboidal..........1. Amblystegium

16. Leaf margins recurved below; rhizoids roughly papillose................................................................ 7. Campylophyllum

16. Leaf margins plane throughout; rhizoids smooth...........................17

17. Leaf cells slightly prorate; stems without a central strand...................................................................12. Leptocladium

17. Leaf cells always smooth; stems with a central strand.....................18

18. Pseudoparaphyllia usually foliose, various in size; costae usually single, strong; leaf margins entire or subentire; cilia appendiculate........................................................5. Campyliadelphus

18. Pseudoparaphyllia filamentous or foliose; costae single, forked, or double, sometimes very short, indistinct; leaf margins distinctly serrulate; cilia nodulose................................ 6. Campylium