LEPIDOSTROBUS **« 187 



spores of Lepidostrobus and allied fructifications are very 

 abundant in the Carboniferous formation, and show a 

 great variety in size and surface-sculpture. Some of 

 these megaspores (which were investigated by Messrs. 

 Kidston and Bennie) appear to be identical with those 

 of Lepidostrobus Veltheimianus ; in addition to the 

 spines, these detached specimens show a curious three- 

 lobed appendage to the membrane of the spore (see 

 Fig. 75, D), which very commonly appears in the 

 sections also. It is probable that this structure, which 

 was of very general occurrence 

 in the megaspores of Lepido- 

 dendreae, formed a passage for 

 the admission of the microspores 

 or of the spermatozoids pro- 

 duced by them. Microspores 

 are often found entangled among 



.... r , Fig. 76. — Lepidostrobus foliaceus. 



the bristles of the megaspores. Megaspore (somewhat coi- 



The megaspores of Lepidos- S^^S 



trobus foliaceus, a Coal-measure 5,™,", New PWokgist. s. 



J Coll. 1217. 



species, of which until recently 



only the microsporangia were known, appear to have 

 numbered not more than four in each sporangium, 

 and possess a curious episporic appendage, comparable 

 to the so-called " swimming apparatus " of Azolla l 

 (see Fig. 76). 



In favourable cases the prothallus is preserved 

 within the megaspore. This is sometimes the case in 

 L. Veltheimianus, as is well shown in Fig. yj ; the 

 prothallus is here almost complete, and fills the 

 megaspore. Fig. 78, from a photograph, represents 



1 R. Scott, New Phytologist, June 1906. 



