Seed-Plants 137 



sperms, emphasizes the very low rank of these primi- 

 tive seed-plants. 



Cycadeoideae. Either from the cycads, or per- 

 haps independently from some of the Paleozoic 

 pteridosperms, there arose a second group of 

 cycad-like plants, which also culminated in the 

 Mesozoic, and were much more specialized than 

 any of the true cycads. These plants have been 

 called " Cycadeoideae," and the most important col- 

 lections of these have been made from the Black 

 Hills region of Dakota and Wyoming. From a 

 study of these fossils (for details see Wieland: 

 "American Fossil Cycads "), which have been very 

 well preserved, our knowledge of the structure of 

 these remarkable forms is very complete. In some 

 of these Cycadeoideae the " flowers " have been very 

 well preserved, and the arrangement of the sporo- 

 phylls, which are borne together upon the same cone, 

 is so much like that of such flowers as the water- 

 lily or magnolia, that some students have actually 

 claimed that these Cycadeoideae are the real an- 

 cestors of the higher flowering plants, the Angio- 

 sperms. It must be remembered, however, that the 

 Cycadeoideae are gymnosperms, that is, the naked 

 seeds are borne free upon the sporophylls and the 

 " stamens " are very unlike those of the angio- 

 sperms, and closely resemble the leaves of the 

 true ferns. Moreover, it may be assumed that 

 the gametophyte was well developed, like that of 

 the cycads, and it would certainly be rash 



