Fam. 15. Schistostegaceee. 
Capsule very small. Calyptra conie.  Prothallium 
persistent. j 
Subtribe 2. Ptychophylle astome. 
Stem with subcomplicate leaves. Peristome none. 
Fam. 16. Hustichiacee. 
Leaves distichous, narrowly alate at the costa; inner 
cells irregularly polygonal, the marginal ones narrow. 
Subtribe 3. Haplostome. 
Stem with not complicate leaves. Peristome simple, 
sometimes wanting. | 
. Section 1. Anarthrodontc. Peristomial teeth solid, 
not articulate. 
Fam. 17. Polytrichacee. 
Peristomial teeth 32 or 64, small and linguiform. 
Leaves with narrow lamellae near the costa; upper cells 
roundish. 
Fam. 18. Georgiacez. 
Peristomial teeth 4, large and nearly subulate. Létvés 
not lamellate. 
Section 2. Arthrodonte. Peristomial teeth trans- 
. versely articulate. 
A. Leaves distichous, with two broad and embracing 
stipular appendages (wings) at the base. | 
Fam. 19. Piauidentatads. 
Y — Peristomial teeth 16, usually cleft. Leaf-cells round- 
. hexagonal or the marginal ones narrow. Plants growing 
. On earth, seldom in springs and rivers. — : 
p B. Leaves plurifarious or (in Disüchium) distichous, 
. without stipular appendages. | 
= Leaves sometimes. papillose | or saajien not rarely | 
; ‘smooth. Plants seldom growinë: on Menu 
