708 



THE SUBDIVISIONS OF THE VEGETABLE KINGDOM. 



fig. 400". In Cyathea (figs. 400 ^''>"'^'') the indusium is cup-like, and closed 

 until the spores are ripe. In Diclcsonia the sorus is marginal, with bivalved indu- 

 sium; in Alsophila the sori are scattered, and the indusium absent or rudimentary; 

 in Hemitelia the indusium is scale-like, and situated on one side of the sorus. Of 

 Cyatheaceae about 200 species are known. 



Fig. 401.— Lile-history of a Fem. 



I A Femprothallium seen from the under side. ' An archegonium in longitudinal section. • An antheridiuni. * Escape of 

 spermatozoids from antheridium. * Young sporopliyte witli first leaf arising from the prothallium. ^ Complete sporo- 

 phyte of Anplenium Huta-muraria. T Under surface of pinnule of same, showing linear sori and lateral indusia. ^ A 

 young protliallium arising from a spore ; the spore is below. « natural size ; i x 8 ;-,*,* x 350 ; * x 6 ; ' x 3 ; 9 x 240. 



Oleicheniacece. — Mostly tropical forms. The sporangia have a transverse annu- 

 lus, and are collected into little sori of 3 or 4 sporangia, often very closely packed 

 (cf. figs. 400 ", and 400 ^). The frond usually forks repeatedly. There is only one 

 genus, Gleichenia, which has some 40 species. 



Schizceacece. — The members of this family are also for the most part ti-opical. 



