320 Systematic Paleontology 



others, like WilKamsonia gigas, are known, in which the fructification 

 appears to be terminal. 



The discovery of the bi-sporangiate nature of Cycadeoidea inaugurated 

 a renewed interest in the cycadophytes. Professor ISTathorst has recently 

 described Williamsonias which were unisexual/ and Wieland, Arber and 

 Parkin, and others," have advanced the theory that these Lower Cre- 

 taceous forms were not very different from the ancestors of the higher 

 plants (Angiospermse) represented in the existing flora by the order 

 Ranales, entirely overlooking the wide difference in structure throughout 

 the vegetative body, where the characters are much more conservative 

 and furnish a much safer clue to filiation than do the reproductive parts, 

 especially when of the indicated plasticity of those of the cycadophytes. 



We may now proceed to the enumeration of species, brief descriptions 

 of which are adapted from Prof. Ward's more voluminous treatment 

 {loc. cit.). 



% 

 Cycadeoidea makylandica (Fontaine) Capellini and Solms-Laubach 



Plate XLII 



Cycas sp., Tyson, 1860, First Report State Agric. Chem., Maryland, p. 42. 

 Bennettites sp., Carruthers, 1870, Trans. Linn. Soc, London, vol. xxvi, 



p. 708. 

 Cycadeoidea sp., Fontaine, 1879, Am. Journ. Sci., 3d ser., vol. xvii, p. 157. 

 Tysonia Marylandica Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 1889, 



p. 193, pi. clxxiv-clxxx. 

 Cycadeoidea Marylandica Capellini and Solms, 1892, Mem. Real. Accad. Sci. 



Inst., Bologna, ser. v, vol. ii, pp. 179, 180, 186. 

 Cycadeoidea Marylandica Ward, 1897, Proc. Biol. Soc, Washington, vol. 



xi, p. 9. 



^ Nathorst, A. G., Ueber Williamsonia, Wielandia, Cycadocephalus und 

 Weltrichia, Kgl. Svenska Vetens.-Akad. Handl., Band xlv, No. 4, 1909. 



" Arber, E. A. N., and Parkin, J., On the Origin of Angiosperms, Journ. 

 Linn. Soc. Lond., vol. xxxviii, 1907; The Relationship of the Angiosperms to 

 the Gnetales, Annals of Botany, vol. xxii, 1908, pp. 489-515. 



Scott, D. H., The Flowering Plants of the Mesozoic Age, in the Light of 

 Recent Discoveries, Journ. Roy. Micr. Soc, 1907, pp. 129-141. 



Wieland, G. R., The Williamsonias of the Mixteca Alta, Bot. Gazette, vol. 

 xlviii, 1909, pp. 427-441. 



