EXPLANATION OF PLATE XXII. 



RICCIA. Plant of R. natans; section of thallus, showing two imbedded 

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

 three free spores; and calyptra with style. 



ANTHOCEROS. Plant of A. lasvis; 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 disk ; an elater, a portion of same, and spores. 



SPH^EROCARPUS. Plant of S. terrestris; cluster of five involucres; in- 

 volucre enclosing a capsule ; capsule filled with spores ; and three spores. 



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

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

 tion of <J disk ; elater and portion of same ; spores. 



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

 involucres ; side view of same ; involucre partly cut away 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 (J disk ; elaters, a part of one, and spores. 



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

 3 receptacle ; perianth, calyptra, and capsule ; section of part of $ disk ; 

 an elater, part of same, and spores. 



FIMBRI ARIA. Plant of F. tenella; 9 receptacle, and section of same; 

 capsule dehiscing ; elaters aud spores. 



PALLAVICINIA. 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. 



