418 Gelehrte Gesellschaften, 



who named it first Lepidostrobus insignis and afterwards Lepido- 

 dendron Spenceri*), wliile the other {Spencerites majuscidus) is new. 



In one of liis latest publications, Williamson pointed out that 

 it might ultimately be necessary to make bis Lepidodendron 

 Spenceri the type of a new geuus.**) The Separation thus sugge- 

 sted is now carried out, on the basis of a renewed investigation 

 of the structure of this fossib 



Spencerites insig-nis is a pedunculate strobilus; the vegetative 

 Organs are not as yet identitied. The specimens are calcified, 

 and their structure admirably preserved. 



The anatomy of the axis is of a simple Lycopodiaceous type, 

 but differs in details (such as the course of the leaf trace bundles) 

 from that of the axis oi Lepidostrobus. The peduncle. bears sterile 

 bracts, similar to the sporophylls of the cone itself ; the latter are 

 arranged spirally, or in some cases in alternating verticils. 



The individual sporophylls are of peltate form, consisting of 

 a short cylindrical pedicel, expauding into a relatively large lamina. 

 The sporangia are approximately spherical bodies; unlike those 

 of Lepidostrobus, they are quite free from the pedicel, and are 

 attached by a narrow base to the upper surface of the lamina, 

 where it begins to expand. 



The details of the sporangial wall are quite different from 

 those of Lepidostrobus, and the spores are characteristic. In size 

 they are intermediate between the microspores and macrospores 

 of Lepidostrobus. They are of tetrahedral form, becoming 

 spheroidal when mature, and each spore has a hoUow, annular 

 wing running round its equator. The wing is no doubt formed 

 by a dilation of the cuticle,***) and not, as Williamson supposed, 

 from the abortive sistercells. 



Spencerites majuscidits, the newspecies, is much larger than the 

 former, the axis of the cone being twice as thick. The anatomy 

 is similar, but the sporophylls, and consequently the leaf-traces, 

 are more numerous. The sporophylls, which are arranged in alter- 

 nating verticils, are relatively short, and of peculiar form; the 

 lamina is very thick, and of great tangential width. The sporangia 

 are like those of the former species, and similarly inserted, but 

 the spores are quite different. They are smaller than those of 

 S. insignis, and hav^e the form of quadrants of a sphere, with 

 narrow wings along their three angles. 



The genus is separated from Lepidostrobus, mainly on account 

 bf the very different mode of insertion of the sporangia, a character 

 which is accompanied by differences in the form of the sporo- 



*) Williamson, „Or^anisations of the Fossil Plants of the Coal- 

 measures". Parts IX, X, XV I,and XIX. (Phil. Trans. 1878, 1880, 1889 and 1893.) 



**) General Index, Part II, 189.3, p. 24. 

 • ***) Cf. Solms-Laubach, Fossil Botany, p. 239. 



