6 }VciT<l XjH'cirx of Oycodeoideo, from Maryland. 



Subkingdom SPERMATOPHYTA. 



ClaSS G YM NOSPE RM JE. 

 Family CYCADACE/E Lindley. 



Subfamily CVCADEOIDE.E Robert Brown. 



Fossil cycadean vegetation of Mesozoic age represented by 

 trunks, foliage, and fruits, and embracing a large number of 

 genera and species, tbe trunks usually not accompanied by other 

 organs than the bases of the leafstalks, and reproductive axes 

 included in a false bark or "armor" generally of considerable 

 thickness; foliage usually also found separate from other parts, 

 and fruits and rarely flowers similarly isolated. The number of 

 genera and species is therefore necessarily duplicated and mul 

 tiplied, owing to the impossibility of correlating the detached 

 parts, but that those found at similar horizons and localities be 

 longed together admits of no doubt. The trunks differ in size 

 and form much as do living Cycadaceae (Cycadeae), and characters 

 of all parts show resemblances to existing genera. It is, however, 

 probably incorrect to say that the latter have descended from 

 the former, or that the fossil forms are embryonic types of the 

 living forms, and the correct conception of the subfamily is em 

 bodied in the law of sympodial development.* according to which 

 the principal trunk line of descent which the fossil forms repre 

 sent, and which attained its maximum development in Mesozoic 

 time, became extinct, while inferior lines or branches represented 

 by living forms persisted into modern times. This accounts for 

 the fact so prominently insisted upon by Count Solms-Laubach 

 and others that the fossil forms, at least those in which the re 

 productive organs are preserved embedded in the armor of the 

 trunks (Bennettites), are structurally more advanced than the 

 living Cycadaceae, a fact which finds its counterpart in the Lepi- 

 dophyta and Calamarhu of the Carboniferous and in the Dino- 

 sauria of the Mesozoic. 



Genus Cycadeoidea Buckland. 



1827. Cycadeoidea Buckland, Proc. Geol. Soc. London, vol. I, Xo. 8, pp. 



80-81 (session of June 6, 1827). 



1828. Cycadeoidea Buckland, Trans. Geol. Soc. London, 2d ser., vol. II, 



pp. 375-401, pi. xlvi-xlix. 



Fossil trunks of Cycadeoidese, chiefly low (30-90 centimeters in height) 

 and more or less conical or oval in shape (15-75 centimeters in diameter), 



*Proc. Biol. Soc. Washington, vol. V, Washington, 1890, p. 24. Lester 

 F. Ward: The Course of Biologic Evolution (reprint of above), p. 2. 



