148 SPORANGIOPHORES AND SPOROPHYLLS 



in regular whorls, instead of irregularly as in Tmesipteris. In other Spheno- 

 phylls the number of sporangia may be less, and the number of the more 



FIG. 77. 



Tmesipteris tannensis, Bernh. A, habit of a whole plant, pendulous form, showing 

 dichotomy. Natural size. -, sporophyll and synangium ; B from the side, C from 

 above, D after dehiscence, E from below, all X about 3. .F=rhizome. ^ size, ^trans- 

 verse section of stem. X4- (After Engler and Prantl.) 



elongated stalks or sporangiophores, greater : thus in 6". Dawsoni they 

 are twice, in S. Rbmeri three times as numerous as the segments of the 



