Geology and Natural History. 475 



course reminding one of recent cycads. But there are two funda- 

 mental differences : firstly, the microsporophylls are far more 

 leafy ; and secondly, the seed cone not only retains an original 

 foliar spiral in which the fertile and sterile organs regularly 

 alternate, but the seed stems, although bearing a single terminal 

 seed enveloped by the pericarp of interseminal scales as in 

 Cycadeoidea, also retain several lateral pairs of abortive seeds, 

 being as truly carpellary leaves as in the case of Cycas. 



Weltrichia thus unites a noteworthy series of characters and is 

 a far older type than either Cycadeoidea or Wiliiamsonia / 

 while the retention of carpellary features, with both fertile and 

 nonfertile organs of the ovulate cone in the original spiral order, 

 places beyond further controversy the reviewer's interpretation 

 of the homology of these organs as given in his American Fossil 

 Cycads (pp. 230-232, etc., etc.). At the time that work was 

 written no undoubted examples of related flowers with spiral 

 insertion of sporophylls could be pointed out, though Mexican 

 ovulate cones of Williamsonian nature with spirally inserted 

 sterile (?) organs of the basal region (cf. fig. 14) were later found. 



Schuster properly lays much stress on this primitive feature 

 and gives a clear diagram explaining once and for all how by 

 simple increase in number of nonfertile organs with lateral appres- 

 sion and compensating change of form the original spiral order 

 comes to be hidden in the ovulate cone of Cycadeoidea. And 

 may not these alternant fertile and nonfertile organs of the Wel- 

 trichia strobilus go to explain the ovuliferous scale of the conifers 

 if Cycadocarpidium fails to do so ? 



Easily the most remarkable character of Weltrichia is of course 

 the retention of carpellary leaf characters in a cone so far 

 advanced in the direction of Cycadeoidea / and it goes without 

 saying that with such rare evidence before him Schuster has been 

 in a position to make still more tangible the idea that types like 

 Weltrichia and Wiliiamsonia are very close indeed to the ances- 

 tral forms leading into the Ranales. And to say the least, this 

 opportunity has been used in a highly effective and interesting 

 manner. The source of the dicotyledonous foliage is at once 

 referred to the old Pterophyllum line, while the facile suggestion 

 is made that in Nelumbium it is the series of organs in the posi- 

 tion of the interseminal scales of Cycadeoidea which is fertile. 



With regard to the strict monophyly of the Angiosperms we 

 cannot of course follow Schuster without some reservation of 

 doubt. The Williamsonian Tribe as the known expression of an 

 enormous Mesozoic-Paleozoic complex may have given rise to 

 lines of descent altogether too varied to fairly accord with any 

 ordinary limit or conception of monophyly. 



That it has, on the other hand, become more difficult than ever 

 before to cite real differences between the Cycadaceans and the 

 Williamsonian alliance can finally escape no one. In fact it 

 appears more and more likely that in pre-Rhatic or Permian time 

 the lines leading into these larger Cycadalean groups were virtu- 

 ally identical. But that the apparent restriction of Weltrichia 



