XV] LEPIDOSTROBUS 187 



to lack of information as to the extent to which the transition 

 from sterile to fertile portions of a shoot is accompanied by 

 anatomical differences. Prof. "Williamson wrote: "I have for 

 many years endeavoured to discover some specific characters by 

 which different Lepidostrobi can be distinguished and identified, 

 but thus far my efforts have been unsuccessful'." In a few 

 cases, such as those mentioned in the description of Lepidoden- 

 dron Veltheimianum and L. Wilnschianum, it has been possible 

 to correlate cones and vegetative shoots. 



The most complete account we possess of the anatomy of 

 Lepidodendron cones is that by Mr Maslen^ who first demon- 

 strated the occurrence of a ligule on the sporophylls, and thus 

 supplied a missing piece of evidence in support of the generally 

 accepted view as to the homology of the sporangium-bearing 

 members and foliage leaves. 



i. Lepidostrohus variabilis (Lindley and Hutton). 



1811. "Strobilus," Parkinson, Organic Kemains, Vol. i. p. 428, 



PL IX. fig. 1. 



1828. Lepidostrohus omatus, Brongniart, Prodrome, p. 87. 



1831. L. variabilis, Lindley and Hutton, Foss. Flora, Pis. x. xi. 



1831. L. omatus, Lindley and Hutton, Foss. Flora, PI. xxvi. 



1837. L. ornatiis var. didymus. Ibid. PI. clxiii. 



1850. Arancarites Cordai, Unger, Genera et Spec. Plant, foss. p. 382. 



1875. Lepidostrohus variabilis, Feistmantel, Palaeontographica, Vol. 



LXIII. PI. XLIV. 



1886. L. variabilis, Kidston, Cat. Palaeozoic Plants, p. 197. 



1890. L. omatus, Zeiller, Flor. Valenciennes, p. 497, PI. LXXVI. 



figs. 5, 6. 

 L. variabilis, Zeiller, Flor. Valenciennes, p. 499, PI. Lxxvi. 



figs. 3, 4. 



Under this specific name are included strobili from Upper 

 Carboniferous rocks which, in spite of minor differences, may be 

 considered as one type. The cylindrical cones vary considerably 

 in size, some reaching a length of 50 cm. or more. The sporo- 

 phylls are attached by a pedicel, 4—8 mm. long, at right angles 

 to the axis, while the distal portion forms an oval lanceolate 

 limb 10—20 mm. in length. The sporangia are 4—8 mm. long. 



1 Williamson (93) p. 26. " Maslen (99). 



