BKYACE^. 27 



the inner base of the teeth, dividing above into 16 lanceolate 

 double segments, which are carinate on the outside by the 

 cohesion of the segments their whole length, or cleft along 

 the divisural hne and disjoined, or adhering merely by promi- 

 nent articulations and thus perforated on the keel ; segments 

 alternating with the teeth of the external peristome and often 

 separated by 1 to 3 filiform articulate or more rarely transversely 

 laciniate or appendiculate cilia. Spores of one kind only, till- 

 ing the inner sac of the capsule, dispersing at maturity and 

 producing by germination the filiform prothalliuni, from which 

 sprout the primitive buds of the plants. 



Systematic Arrang-ement of Tribes and Genera. 



Series I. ACROCARPI. Flowers terminal, becoming lateral only 

 by innovations from under the flowers. 



A. Dehiscence of the capsule irregular, transverse. 



Teibe I. PHASCE^. Plants minute. Leaves soft, very loosely areo- 

 late. Capsule globular, immersed, subsessile or short-pedicellate. 



« Plants bud-like, on a persistent prothallium. Leaves nerveless, except 



in one species. 



Calyptra minute, closely adhering. 1. Micronaitrium. 



Calyptra larger, campanulate. 2. Ephemerum. 



* * Leaves distinctly nerved, Prothallium none. 



Caulescent. Capsule globose, apiculate. 



Calyptra campanulate. 3. Physcomitrella. 



Stemless. Capsule enclosed in a cluster of 



imbricate concave leaves. 4. Spheerangium. 



Caulescent. Capsule pedicellate. Calyptra 



cucullate. 5. Phascum. 



Plants larger; stems divided. Capsule ovate. 



Calyptra cucullate. 6. Pleuridium. 



Stemless. Leaves more closely areolate, mi- 

 nutely papillose on the back. 7. Microbryum. 

 Caulescent. Capsule apophysate, except in 



one species. Calyptra mitrate. 8. Bruchia. 



Capsule globose. Calyptra irregularly torn. 



Spores very large and few. 9. Archidium. 



B. Capsule dehiscing by a deciduous operculum. 



Tkibe II. WEISIE^^. Plants cespitose. Leaves simply costate; areo- 

 lation opaque, punctiform or quadrate, generally papillose in the 

 upper part, oblong-hexagonal, pellucid or chlorophyllose in the 



