THE ORIGIN OF THE "FLOWER" 259 



Passing on, now, to the next great geological epoch, viz. 

 the Mesozoic, we find abundant remains of plants both in 

 Europe and, more especially numerous, in the United States 

 of America, which are known as the Cycadeoideae or Cycad- 

 like plants, or sometimes as the Bennettiteae. Just as the 

 " Seed-ferns " may be regarded as forms intermediate in char- 

 acter between the true Ferns and Gymnosperms generally, so 

 these Cycadeoideae may be regarded as being intermediate 

 between the " Seed-ferns " and our modern living Cycads. The 

 structure, both external and internal, of their stems and of their 

 leaves, as well as their general habit, is almost identical with 

 that of the Cycads. But in the character of the reproductive 

 organs they diverge widely from those plants. Unlike the 

 " Seed-ferns," the sporophylls of the Cycadeoideae differ 

 altogether from the vegetative or foliage leaves of this group ; 

 these latter resembled those of modern Cycads, consisting each 

 of an elongated rachis bearing on each side a row of simple 

 undivided pinnae, being thus much simpler in organisation than 

 the foliage-leaves of the " Seed-ferns." Now, while it is true 

 that the sporophylls of some members of the latter group were 

 considerably reduced as regards the laminar development of 

 their fronds, yet they still exhibited the same general com- 

 plexity of subdivision into minute segments as the foliage- 

 leaves, and it is not unlikely that the two kinds of foliar organ 

 were mixed together on the plant, or, at any rate, were borne 

 on the same main axis. But in the Cycadeoideae the sporophylls 

 are restricted to special, very short branches occurring in the 

 axils of certain of the leaves of the main stem. Dr. G. R. 

 Wieland, of Yale University, Connecticut, has described 1 for 

 us numbers of these plants, which he has obtained chiefly from 

 the Black Hills of Dakota. The peduncle of the short fertile 

 branch or cone is clothed with simple bracts, which enclose 

 it entirely in the bud-condition. At the upper end of the 

 peduncle, where the bracts cease, is borne a whorl of male 

 sporophylls, which are connate below to form a kind of cup 

 or enclosing wall. The complexity of organisation of these 

 male organs reminds one again of those of the Seed-ferns, and 

 indeed they are very Fern-like, although it is evident that very 

 considerable reduction in complexity has taken place during 

 their descent from the sporophylls of the Seed-ferns. For 



1 American Fossil Cycads, 1906. 



