THE GAMETOPHYTU 



125 



The germination of the spores and the early stages are quite unknown in 

 Daticea, but probably resemble those of the other genera which have been studied. 

 To judge from the younger stages collected, there is a good deal of variety of form, 

 as is the case also in the other Marattiacea?. The youngest specimens collected 

 belonged to D. jamaicensis. These were very broad in outline and unsymmetrical, 

 one wing of the prothallium being much better developed than the other (fig. 91, B). 



Fk.. 01.— Foul gametophytes of D. elliptica Smith. XI. B-D, seen from belov, . 



Fig. 92 shows some older specimens of D. elliptica which were greatly elongated, 

 the very much attenuated posterior region being quite thin and delicate in texture, 

 with no midrib and the archegonial cushion being confined to a small region just 

 back of the growing point. The marginal region in these young prothallia was 

 composed of a single layer of cells and a considerable portion was made up of but 



Fig. 93. 



A. Young gamctophyte, probably developed from an adventitious bud "I Datura jamaicensis. 



X20. ff antheridia. 



B. Large gametophyte of D. elliptica, with two sporophytes. Xi. 



C. Multicellular rhi/.oid. Xioo. 



D. A cell of the rhizoid, showing nucleus, if. X210. 



two layers, while the mid region, where the antheridia and later the archegonia are 

 developed, was not more than four to five cells in thickness. In general the prothallia 

 of Daneea a re ]m ore delicate in texture than those of the other Marattiacea? that 

 have been studied. 



