9. Zygodon Hook. & Taylor   变齿藓属   bian chi xian shu

Muscol. Brit. 70. 1818. Zygodon sect. Zygodon (Hook. & Taylor) Müll. Hal., Linnaea 18: 670. 1845.

 

Plants slender, green, yellowish green or dark brown, in loose or dense mats. Stems erect- or spirally ascending, simple or branched, with dense reddish rhizoids. Leaves appressed, often twisted or contorted when dry, erect-spreading or recurved to squarrose when moist, mostly lanceolate to elongate-lanceolate, long acuminate, or elongate-lingulate, obtuse; margins plane, entire or dentate near the apex; costae strong, subpercurrent, rarely shortly excurrent; upper leaf cells rounded-hexagonal, thick-walled, unipapillose, or smooth; lower cells gradually elongate, rectangular, hyaline. Gemmae often present on stems or leaves. Dioicous or autoicous. Perichaetial leaves not differentiated. Setae elongate; capsules oblong-ovoid, constricted at the mouth, clearly plicate or furrowed, apohyses present; opercula conic, usually long-rostrate; annuli differentiated, often persistent; peristome double, single (only endostome present) or absent; exostome teeth 16, partially or completely united in 8 pairs, densely papillose above, trabeculate on the outer surface, striolate with dense papillae at base; endostome segments 8 or 16. Calyptrae small, cucullate, deciduous, usually smooth, rarely hairy. Spores spherical, papillose.

 

1. Leaves broadly obtuse at the apex............................................................................................... 2. Z. obtusifolius

1. Leaves acute or apiculate at the apex...................................................................................................................... 2

2. Leaf margins irregularly dentate at the apex............................................................................ 3. Z. reinwardtii

2. Leaf margins entire throughout........................................................................................................................... 3

3. Leaves ovate-lanceolate, shortly blunt or apiculate at the apex................................................... 1. Z. brevisetus

3. Leaves narrowly lanceolate, acuminate at the apex............................................................................................... 4

4. Leaves erect, not or somewhat contorted when dry; gemmae 5–10 cells long, fusiform, ellipsoid, subclavate................................................................................................................................. 4. Z. viridissimus

4. Leaves twisted, flexuose, appressed when dry; gemmae absent........................................ 5. Z. yuennanensis