254 HISTORY OF BOTANY 



the Flora of the Carboniferous epoch, certain other 

 discoveries began to throw light on the much-debated 

 question as to the origin of the Angiosperms. 



In the Mesozoic rocks remains of many Cycad-like 

 plants had been found whose fructifications, however, 

 did not seem to bear any resemblance to those of recent 

 forms. One of these fossils was described by Carruthers 

 as far back as 1868 under the name of Bennettites, known 

 at a later date also under the name Cycadeoidea, more 

 especially in America, where plentiful remains had been 

 discovered. So far as its stem structure was concerned 

 it seemed to fit into the Cycad series, although its anatomy 

 was of a somewhat simpler type ; the chief point of differ- 

 ence seemed to be that it possessed many lateral branches 

 whose origins were imbedded between the leaf bases 

 with which the surface of the stem was covered. These 

 lateral branches carried the fructifications which were 

 conical or pyriform structures, consisting of a convex 

 thalamus whence arose externally a number of bracts 

 enclosing a large number of seeds with long funicles, 

 separated from each other by interseminal scales whose 

 distal ends expanded, closely covering the terminal seeds, 

 and forming a sort of pseudo-pericarp through which the 

 micropyles of the seeds protruded. As in the case of the 

 Pteridosperms, I must refer you for details to the published 

 accounts of this remarkable plant, otherwise these lectures 

 will tend to become a textbook of botany, to write which 

 is not at all my intention. 



The seed contained a well-marked dicotyledonous 

 embryo with scarcely any endosperm, a fact first recog- 

 nised by Solms Laubach in 1890 ; in this respect it 

 differs from all members of the modern Gymnosperm 

 series. 



In 1899, owing to the researches of Wieland, we 

 began to learn something of these Cycad-like plants as 

 they were represented in the Mesozoic strata of Dakota. 

 In that year Wieland discovered the stamens, and in 



