THE VASCULAE CRYPTOGAMS 



kind (the megasporangium or macrosporangium) contains 

 only four spores, megaspores or macrospores, but these 

 spores are so large that the sporan- 

 gium which contains them has to be 

 much larger than that which holds 

 the innumerable microspores (see 

 Fig. 4). 



Both kinds of sporangia are borne 

 on the same cone ; generally the micro- 

 sporangia are the more numerous, and 

 occupy the axils of all the upper 

 leaves of the cone, while the few 

 megasporangia are found at the base 

 of the cone only. The arrangement, 

 however, varies in different species. 



mi i -i i r. ,1 Fro. 5. Selaqinella 



The development and structure of the sninosa ; fertile 

 sporangia will be further described spike. Magnified 



, , H diameters. 



below. (Vv. C. W.) 



II. INTERNAL CHARACTERS OF THE VEGETATIVE 



ORGANS 



Among the Flowerless Plants we find a very great 

 variety in characters, which in the Phanerogams remain 

 fairly constant throughout whole Classes. 



This holds good especially for the internal structure. 

 A description of the anatomy of the Wallflower was 

 sufficient to give a fair general idea of the chief 

 anatomical features of the Dicotyledons generally, and 

 BO it was with our other types of flowering plants. 

 With the Cryptogams the case is quite different. Not 

 only is the anatomy of Selaginella peculiar to that one 

 genus among plants now living, but the variation of 



