246 PLANT-LIFE 



the Arctic and Antarctic regions, indicating a warm 

 climate where now snow and ice prevail. 



Modern Cycads, particularly of the genus Cycas, have 

 been found fossil, but in speaking of Mesozoic Cycads 

 we refer to a vast group of many genera, which we more 

 aptly designate " Cycadophytes," and of which the great 

 majority appear to have been much more highly organ- 

 ized than the relatively simple modern forms. I am 

 referring to the Bennettitese, which were much like 

 existing Cycads in general habit, but differed 1 from them 

 in a marked degree as to their reproductive organs. In 

 the Cycads of to-day the sexes are represented on dif- 

 ferent plants, but in the Bennettitese the cones, borne 

 laterally, and of a flower-like appearance, were herma- 

 phrodite that is, they included both sexes. We may, 

 indeed, speak of the cones as " flowers," for they con- 

 sisted of bracts, staminal leaves bearing many pollen 

 sacs, and stalked ovules, which, after fertilization, 

 developed into seeds of the dicotyledonous type. 

 Here, indeed, we have a suggestion of true Flower- 

 ing plants, and it is possible that in the fossil Ben- 

 nettiteae we have an evolutionary side issue from 

 the main stock which ultimately yielded the Angio- 

 sperms. 



As to the all-important Angiosperms themselves, we 

 find fossil remains of both Monocotyledons and Dico- 

 tyledons in Upper Cretaceous strata, but the fossils are 

 principally impressions of leaves, not petrifactions ; hence 

 determination of species is difficult. It is interesting to 

 realize that in the later Mesozoic we come suddenly upon 

 Angiosperms, which increased as the Cycadophytes and 

 other groups waned, and which, through Cainozoic to 



