Hypnum.] BRYACE^. 317 



Key to the Subgenera. 



A. Plants pinnately divided. 



* Leaves papillose; paraphyllia more or less numerous. 



1. Pseudoleskea. Branches long and slender, irregularly pinnately 



ramulose. Leaves open-erect; areolation compact, punctiform. 

 Capsule subcernuous; cilia slender or none. 



2. Heterocladium. Stems divaricate and pinnately ramulose. 



Leaves spreading or recurved, those of the perichtetium squar- 

 rose; cells punctulate, the medial elongated-oval. Capsule hori- 

 zontally curved. 



3. Thuidium. Stem regularly pinnately ramose and ramulose. Stem- 



leaves smaller; costa translucent. Capsule cernuous • operculum 

 conic-rostrate. 



* « Leaves papillose; paraphyllia none. 



4. Claopodium. Stems in compact tufts, irregidarly pinnate-ramu- 



lose. Leaves open-erect, denticulate; cells small, oval-fusiform. 

 Capsule turgid, abruptly bent down at the base of the coUum. 



* * * Leaves smooth ; paraphyllia present. 



5. Elodium. Branches long, pinnately ramulose. Leaves striate; 



areolation loose, rhomboidal, uniform. Capsule large, cernuous. 



* « * * Leaves smooth, bicostate; paraphyllia none. 



6. Tripterocladium. Stems compressed and branches attenuated, 



irregularly pinnate. Leaves erect-spreading; cells elliptical, the 

 alar quadrate. Capsule cylindrical, cernuous; cilia solitary, 

 slender. 



B. Plants variously divided. Leaves smooth, simply costate (or bicostate 



in n. 12 and 13). 



* Capsule large; lid conical, acuminate. 



7. Camptotheciutn. Stem densely subpinnately ramulose. Leaves 



plicate; areolation very narrow, linear, very small, square or 

 punctiform at the base and angles. 



8. Brachythecium. Plants large, prostrate, irregularly divided, the 



branches erect. Leaves costute to the middle or above ; areolation 

 loose, elongated-rhomboidal, enlarged at the base and angles. 



9. Scleropodium. Plants densely cespitose, irregularly branching. 



Leaves serrulate; areolation short and narrow, vermicular, en- 

 larged and pellucid at the decurrent angles. 



10. Isothecium. Primary branches dendroid; branchlets stolonif- 



erous or flagellate. Leaves smooth or slightly papillose on the 

 back; areolation very narrow, linear, pimctiform at the angles. 

 Capsule oblong, suberect or cernuous; cilia short. 



* * Capsule horizontally Inclined; lid rostrate. 



11. Eurhynchium. Plants pinnately ramulose. Leaves cordate, 



decurrent, sex'rate; areolation rhomboidal-oval. Capsule turgid- 

 oval. 



12. Raphidostegium. Plants small ; stems prostrate and com- 



pressed. Leaves ecostate or shortly bicostate; areolation minute, 

 linear, flexuous, the basilar cells very few and inflated. Capsule 

 suberect or cernuous. 



