398 SCIENCE PROGRESS 



remarkable discoveries it is no longer possible for systematists 

 to lay stress on the simplicity of the trimerous flowers of 

 Monocotyledons or the reduction shown by the flowers of 

 the Amentiferce or of other so-called Apetalce as indicating 

 primitive relics of the ancestral forms of flowering plants. 

 Palaeontology itself seemed to lend some countenance to the 

 earlier view, which held the field for so long, for the earliest 

 known remains of Angiosperms, occurring in the Neocomian of 

 Portugal and the United States, were identified for the most 

 part as members of the catkin-bearers, such as Myrica, etc. 



Wieland's researches on the Bennettitece have clearly shown 

 that the members of this group possessed strobilate flowers, 

 which must have been closely allied in structure to those of 

 the primitive Angiosperms, for they evidently stood very near 

 to the direct line of descent. It is sufficient for the present 

 purpose to adopt his generalised diagram of the flower which 

 he considers to be typical of the Bennettitece or Pro-Angiosperms 

 (as Saporta^ with almost prophetic instinct named them at an 

 earlier date on very insufficient material). Here, e.g. in Cycade- 

 oidea dacotensis, we find a conical axis or receptacle on which 

 the ovules (separated from each other by bracts) are ranged 

 in dense order. These are surrounded by a whorl of 18-20 

 stamen-bearing fronds, which in turn are enveloped by a 

 hundred or more, hairy, sterile bracts arranged in spiral phyl- 

 lotaxis. The male fronds or microsporophylls each bear twenty 

 pairs of alternate pinnae, on which are ranged ten rows of sori 

 or synangia (closely resembling the synangia of the euspo- 

 rangiate fern Marattia), showing affinities with the fern-like 

 Pteridosperms to a greater degree than the reduced and more 

 specialised megasporophylls or ovules. It is, however, intelli- 

 gible and only natural that the organs which are the most 

 essential to the continuance of the race, i.e. the female elements, 

 should have advanced more rapidly than the male organs ; and, 

 as a matter of fact, it is well known that the Pteridosperms 

 had attained to the production of seeds at least as far back 

 as the Carboniferous period. The great stride in advance that 

 the Bennettitece had made upon the Pteridosperms was eff'ected 

 by the evolution of a strobilus, in which the male and female 

 organs were grouped together and protected by spirally 

 arranged foliar structures (a primitive perianth according to 

 ' Saporta, G. de, Plaiitcs Jurassiques, vol. iv. Paris, 1891. 



