324 



CONES AND SPOROPHYLLS 



collected together in small groups ; they dehisce by a wide split. 

 In most cases the megasporophylls are of a similar nature, although 

 they produce only two megasporangia, usually placed one on 

 either side of the stalk-like lower part (Fig. i86, B) ; the mega- 

 sporangia are of a peculiar tj'pe and are known as ovules. In 

 Cycas, however, the megasporophjdls are very leaf-like, although 

 relatively small, hair}', and brown in colour, and often bear 



Fig. 185, — A, Entire male cone of Bowenia speciahilis, and B, part of the 

 same in longitudinal section, showing the microsporangia (s/>.) on the 

 lower surfaces of the sporophylls. C, Upper, and D, lower surface of 

 a microsporophyll of Cycas. sp., microsporangia. E, Part of a pinna 

 of the leaf of Eiicephalartos to show the veining. 



more than two of these ovules (Fig. 1S6, A). The female plant 

 of Cycas can, as a matter of fact, be profitably compared with 

 such a Fern as Blechnnin (cf. p. 308), since in both cases the 

 sporangia occur on fronds which are but little modified. An 

 examination of the megasporophylls of different Cycads shows 

 aU stages in the reduction of the lamina to a condition in which 

 the leafdikc character is almost entirely obscured [e.g. EnecpJm- 

 lartos, Fig. 186, B). 



The ov2iles (inegasporatigia) (Fig. 1S6, C and D) arc of con- 



