EXPLANATION OF PLATE XXII. 



RICOIA.-- Plant of K. natans; section of thallus, showing two imbedded 

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

 three free spores; and calvptra with stvle. 



ANTIKX'KKOS. - Tlant of A. huvis ; portion of the columella and valves of 

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



X< >T< )TII YLAS. Plants of N. orliicnlaris ; section of the thallus through 

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

 tin- columella ; upper half of capsule ; a gemma ; an antheridium ; twelve 

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



ASTERELLA. Plant of A. hemisph;erica ; 9 receptacle viewed from 

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

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



SPILKUnCAUITS. Plant of S. terrestris; cluster of five involucres; in- 

 volucre enclosing a capsule; capsule tilled with spores; and three cporcs. 



DFMOIJTIKKA. Portions of J and 9 plants of 1). hirsuta ; 9 receptacle 

 showing three involucres, two with capsules ; capsule with calvptra ; 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 parti v cut away showing cap- 

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

 a piece of same, and spores. 



COXOCKPIIAU S. Parts of g and 9 plants of C. conicus; section of 9 

 receptacle, showing two involucres and capsules; capsule with ruptured 

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



I'KKISSIA. Parts of and 9 plants of P. coinmntata : section of 9 re- 

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

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



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

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

 an elater, part of same, and spores. 



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

 capsule dehiscing; elaters ami spores. 



PALLAVICIXI A. 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. 



