372 Systematic Paleontology 



has not been demonstrated for but a few of the fossil species of either 

 Baiera or Oinkgo. 



The staminate sporophylls are in lax strobili not very different from 

 those of the modern Ginkgo, the micro-sporophylls are stalked and 

 expand distally into from three to twelve sporangia which open by longi- 

 tudinal slits. In SchenFs figures of Baiera Munsteriana Heer the 

 sporangia are in clusters of six or seven, while in the excellent examples 

 of Baiera furcata Heer figured by Leuthardt (1903), they are three 

 or four in number, exactly as is sometimes the case in the modem 

 Grinkgo/ The megasporangia (carpels) in Baiera were apparently 

 always more than two in number (the usual number in Ginkgo^), and 

 were borne on short branching stalks. It is worthy of mention in this 

 connection, that some of the older Potomac forms described as species 

 of Ca7'polithus, eg. C. fasciculatus Font., C. ternaius Font., C. virginien- 

 sis Font., etc., are possibly Baiera carpels. 



The genus appears in the Permian of both Europe and America, and 

 continues after the close of the Lower Cretaceous (Earitan formation of 

 ISTew Jersey, Atane beds of Greenland). It is very abundant in the 

 Rhsetic beds and continues to be a prominent element in Mesozoic 

 floras throughout the Jurassic and well into the Lower Cretaceous, 

 occurring most abundantly, perhaps, in the Jurassic. 



Baiera egliosa Fontaine 

 Plate LIX 



Baiera foliosa Fontaine, 1890, Mon. U. S. Geol. Survey, vol. xv, 1889, p. 213, 

 pi. xciv, fig. 13. 



Description. — " Leaves numerous, grouped in bundles or tufts at the 

 summit of short, stout, annual growths, having their basal portions 

 long, slender, and gradually narrowing into a pedicel; their upper por- 



^ Coulter records as many as three or four sporangia in occasional modern 

 Ginkgo sporophylls although normally the sporangia are two in number. 

 Morph. of Spermatophytes, vol. i, 1901, p. 38. 



^ Both Strasburger, Fujii, and Seward and Gowan record instances in which 

 these shoots in the modern Ginkgo bear several ovules. 



