CHAP. XII LEPTOSPORANGIATyE HETEROSPOREA£ 



379 



multiply with extraordinary rapidity. The sporangia arc 

 enclosed in a globular or oval " sporocarp," which is really an 





v*' 





Fig. ig6.—Sahn>iia nutans (L.). A, Small plant, X2, seen from above; B, a similar one from 

 below; iv, root-like submerged leaf; C, fragment of a fruiting plant, X2; sp, sporocarps ; 

 D, a macrosporangial {ma) and microsporangial {mi) sporocarp in longitudinal section (slightly 

 magnified); E, male prothallium with the single antheridium (««) from the side, X 1000 ; F, a 

 similar one seen from above ; G, spermatozoid (Figs. C, D after Luerssen). 



indusium, much like that of some of the Hymenophyllaces and 

 Cyatheaceae. 



