88 



VASCULAR CRYPTOGAMS 



FIG. 64. A, germinating spore and prothallium of Hy7neno- 

 phyllnm ; , C, Z>, stages in development of prothallium 

 (x 120). (After Luerssen.) 



FIG. 65. Prothallium of Osutunda 

 regalis L. a, antherids ; w, 

 rhizoids; v, growing point. (After 

 Goebel.) 



Zealand ; Hymenophyl- 

 lum and Trichomanes 

 nearly 100 species each, 

 exceedingly delicate and 

 graceful ferns, growing 

 mostly on the trunks of 

 trees and damp rocks, 

 often within reach of the 

 spray of waterfalls, in the 

 moister and warmer parts 

 of the globe. The smaller 

 species of Hymenophyl- 

 lum are known as * filmy 

 ferns.' The Hymeno- 

 phyllaceae may be re- 

 garded as the simplest 

 and are probably the oldest 

 family of ferns, and pos- 

 sibly form a connecting link be- 

 tween the Muscinese and the Vas- 

 cular Cryptogams. 



LITERATURE. 



Mettenius Ueber die Ftymenophyl- 

 laceen, 1864. 



Janczewski and Rostafinski (Prothal- 

 lium) Mem. Soc. Nat. Sc. Cher- 

 bourg, xix., 1875. 



Goebel (Germination) Ann. Jard. Bot. 

 Buitenzorg, vii., 1887, p. 57. 



Prantl Untersuchungen zur Morpho- 

 logic derGefasskryptogamen, Heft I. 



Bower Annals of Botany, vol. i., 1887, 

 pp. 183 and 269. 



ORDER 5. OSMUNDACE^E. 



The prothallium of the Os- 

 mundaceae is characterised by its 

 strong tendency to propagate itself 

 vegetatively, by means of adventi- 

 tious shoots, and is commonly 

 dioecious, springing directly from 

 the spore. It is usually ribbon- 

 shaped, with a well-defined midrib 



