LEPIDOSTROBUS 189 



of reproduction in many of the Lepidodendreae agreed 

 closely with that of the heterosporous Lycopods of 

 the present time, but certain other fructifications of the 

 same group attained, as will be explained below (§ 4), 

 a much higher organisation. 



3. Spencerites. — The chief generic character of 

 Lepidostrobus, distinguishing it from most other Lyco- 

 podiaceous strobili, is to be found in the great radial 

 elongation of the sporangium, and its attachment by a 

 long and narrow insertion to the upper surface of the 

 sporophyll-pedicel throughout its length. There is 

 another form of Lycopodiaceous cone from the Coal- 

 measures, which differs in this, as well as in other 

 important points, from Lepidostrobus, and which has 

 therefore been separated, under the name of Spencerites} 

 This type will now be shortly described, and the 

 description will be based, in the first instance, on 

 Spencerites insignis (Will.), the smaller of the two 

 known species. 



The strobilus, which is from 8 to 10 mm. or more in 

 diameter, is pedunculate, the peduncle bearing scattered 

 bracts. The sporophylls are in some cases arranged in 

 regular alternating verticils, of about ten members each, 

 though a spiral arrangement has also been met with. 

 As Miss Berridge has shown, the sporophyll consists of 

 a narrow pedicel, about 2.5 to 3 mm. long, carrying an 

 upturned lamina with a broad fleshy base. The lamina 



1 See Scott, " On the Structure and Affinities of Fossil Plants from the 

 Palaeozoic Rocks, ii. On Spencerites," a New Genus of Lycopodiaceous 

 Cones, Phil. Trans. Roy. Soc. vol. 189, B, 1897. The earlier papers by 

 Williamson are there cited. See also Miss E. M. Berridge, F.L.S.,'"On 

 two New Specimens of Spencerites insignis" Annals of Bot. vol. xix. 1905. 



