Maryland Geological Survey 313 



Phylum SPERMATOPHYTA 



Class CYCADOPHYTAE 



Order BENNETTITALES 



Family CYCADEOIDEACEAE 



Genus CYCADEOIDEA Buckland 

 [Proc. Geol. Soc. Loud., vol. i, No. 8, 1827, pp. 80, 81] 



Trunks usually low and more or less conical or ovoid in shape; gen- 

 erally simple; covered with a thick armor formed by the appendicular 

 and reproductive organs, the former consisting of the persistent bases 

 of the leaf -stalks surrounded by a dense mat of ramentum; trunk 

 crowned with a large terminal vegetative bud often poorly preserved or 

 obliterated by decay before f ossilization ; ramentum made up of very 

 fern-like, multicellular hairs or scales, and extensively developed. Its 

 resistant nature led to its ready petrifaction so that normally the fossil 

 trunks show the ramental areas as prominent partitions separating the 

 subrhombic angular cavities left by the leaf-stalks which decayed or 

 were shed before fossilization. These leaf-scars are arranged in a more 

 or less exact quincunx order, and usually in two sets of spirals, one dex- 

 tral and the other sinistral, the one generally more emphasized than the 

 other. 



The generic separation and nomenclature of the fossil cycad trunks 

 (so called) based on their external form and surface features is one 

 beset with many difficulties, and a great variety of names have been pro- 

 posed for their reception."" Following Professor Ward, the Maryland 

 forms are all referred to Buckland's genus Cycadeoidea, which has pri- 

 ority among the names proposed for tuberous armored types of cycad 



^ Such as GlatJiraria Schimper 1872, Yatesia Carruthers 1870, Fittonia Carr. 

 1870, Platylepis Sap. 1875, Buclclandia Presl 1825, Mantellia Brongn, 1828, 

 Tysonia Font. 1889, Bolbopodium Sap. 1875, Cylindropodium Sap. 1875, Pala- 

 tylepis Sap. 1875, Clathropodium Sap. 1875, Gycadeomyelon Sap. 1875, Rau- 

 meria Carr. 1870, WilUamsonia Carr. 1870, Crossosamia Carr. 1870, etc., many 

 of course being synonyms. 



