263 



from the Permian of Virginia, B. Rmjmondi, Een./ from Charmoy, 

 and some other species. The genus was probably -most widely 

 spread during the Jurassic period, but there is fairly strong evidence 

 in favour of extending its range to the Palaeozoic epoch. In 

 considering the range of Baiera it is important to bear in mind the 

 absence of any well-marked distinguishing features between some 

 species of this genus and some of the more dissected forms of 

 Ginlcgo leaves. Among Jurassic leaves of the Ginkgo type — e.g. 

 G. digitata (Brongn.) and Baiera PhilUpsi, Nath. — it is easy to 

 select a series illustrating a gradual transition from leaves with 

 an entire lamina to those with a dissected lamina and linear 

 segments, conforming in all respects to Braun's genus Baiera, and 

 to leaves which some authors include in the genus Jeanpaulia? 



1. Baiera gracilis, Bunbury, ex Bean MS. 



[Quart. Joui-n. Geol. Soe. p. 182, pi. xii. fig. 3, 1851.] 



(PL IX. Figs. 3 and 5.) 



1851. Baiera? gracilis, Bunbury, Quart. Journ. Geol. Soe. vol. vii. p. 182, 



pi. xii. fig. 3. 

 1854. Baiera gracilis, Morris, Brit. Foss. p. 3. 

 1856. Cijclopteris gracilis, Zigao, Flor. foss. Oolit. vol. i. p. 104. 

 1864. Baiera gracilis, Leckenby, Quart. Journ. Geol. Soe. vol. xx. p. 76. 

 1873. Cf. Jeanpatilia Imigifolia, Saporta, Pal. Franc;, p. 464, pi. Ixvii. fig. 1. 



J. ohtusa, ibid. pi. Ixvii. fig. 2. 

 1875. Baiera gracilis, Phillips, Geol. Yorks. p. 199, lign. 8. 

 1890. Baiera gracilis, Scbenk, in Zittel's Handbuch, p. 262. 

 1892. Baiera gracilis, Fox-Sti-angways, Tab. Foss. p. 137. 

 1900. Baiera gracilis, Seward & Go-n-an, Annals Bot. vol. xiv. pi. x. figs. 6-8. 



Type-specimen. The Bunbury Collection, Botanical Museum, 

 Cambridge. 



Leaf stalked, the lamina fan-shaped, divided into several forked 

 linear segments, each traversed by a few veins. The petiole is 

 long and narrow, branching at the summit into equal branches, 

 which bifurcate repeatedly and spread out in a fan-shaped form ; 

 the ultimate segments are linear, and terminate in a more or 



1 Renault (96), p. 138, fig. 51. 



2 Seward & Gowan (00), p. 138. 



