EXPLAXATIOX OF PLATE XXIL 



RICCIA. — Plant of R. natans; section of thallus, sho-wing tw^o imbedded 

 capsules and numerous air-cavities; spores enclosed in a mother-cell; 

 three free spores ; and calyptra with style. 



AKTHOCEROS. — Plant of A. Isevis; portion of the columella and valves of 

 the capsule, with spores and elaters ; two spores and two elaters. 



NOTOTHYLAS. — Plants of N. orbicularis; section of the thallus through 

 the involucre ; apex of protruding capsule ; lower half of capsule showing 

 the columella; upper half of capsule ; a gemma; an antheridium; twelve 

 free spores, and two clusters of spores (4 in each). 



ASTERELLA. — Plant of A. hemisphaerica; 9 receptacle viewed from 

 above ; the same from below ; capsule dehiscing, with remains of calyp- 

 tra at base ; section of J disk ; an elater, a portion of same, and spores. 



SPH JEROCARPUS. — Plant of S. terrestris ; cluster of five involucres ; in- 

 volucre enclosing a capsule; capsule filled M'ith spores; and three i-pores. 



DUMORTIERA. — Portions of $ and 9 plants of D. hirsuta ; 9 receptacle 

 showing three involucres, two with capsules ; capsule with calyptra ; sec- 

 tion of ^ disk ; elater and portion of same ; spores. 



AITOXIA. — Plant of A. Wrightii ; upper view of 9 receptacle with three 

 involucres; side view of same; involucre partly cut aAvay showing cap 

 sule and remains of calyptra ; a capsule closed, and dehiscent ; an elater, 

 a piece of same, and spores. 



CONOCEPHALUS. — Parts of $ and 9 plants of C. conicus ; section of 9 

 receptacle, showing two involucres and capsules ; capsule with ruptured 

 calyptra; section of ^ disk; elaters, a portion of one, and spores. 



PREISSIA. — Parts of $ and 9 plants of P. commutata ; section of 9 re- 

 ceptacle ; perianth opened showing calyptra and capsule ; section of part 

 of $ disk ; elaters, a part of one, and spores. 



MARCHANTIA. — Parts of $ and 9 plants of M. polymorpha; section of 

 9 receptacle ; pei-ianth, calyptra, and capsule ; section of part of $ disk ; 

 an elater, part of same, and spores. 



FIMBRIARIA. — Plant of F. tenella; 9 receptacle, and section of same; 



capsule dehiscing ; elaters and spores. 

 PALLAVICIXIA. — Plant of P. Lyellii ; part of thallus with involucre, peri- 

 anth, and calyptra ; perianth cut away showing young calyptra; capsule 

 closed, and dehiscent ; antheridium enclosed in a leaf ; elater and spores 



