9 



Fatn. 15. Schistostegaceae. 



Capsule very small. Calyptra conic. Prothalliuni 

 persistent. 



Subtribe 2. Ptychophyllae astomse. 



Stem with subcomplicate leaves. Peristome non&. 



Fam. 16. Bustichiacese. 

 Leaves distichous, narrowly alate at the costa; inner 

 cells irregularly polygonal, the marginal ones narrow. 



Subtribe 3. Haplostomae. 



Stem with not complicate leaves. Peristome simple,, 

 sometimes wanting. 



Section 1. Anarthrodontce. Peristomial teeth solid,, 

 not articulate. 



Fam. 17. Polytrichacese. 

 Peristomial teeth 32 or 64, small and linguiform. 

 Leaves with narrow lamellae near the costa; upper cells 

 roundish. 



Fam. 18. Georgiaoese. 



Peristomial teeth 4, large and nearly subulate. Leaves 

 not lamellate. 



Section 2. Arthr^odontw. Peristomial teeth trans- 

 versely articulate. 



A. Leaves distichous, with two broad and embracing 

 stipular appendages (wings) at the base. 



Fam. 19. Fissidentaceae. 



Peristomial teeth 16, usually cleft. Leaf-cells round- 

 hexagonal or the marginal ones narrow. Plants growing 

 on earth, seldom in springs and rivers. 



B. Leaves plurifarious or (in Distichium) distichous, 

 without stipular appendages. 



Leaves sometimes papillose or mamillose, not rarely- 

 smooth. Plants seldom growing oh trees. 



