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XI. The Structure of Lepidostrobus. By Arthur John Maslen. [Communicated hy 



D. H. Scott, Ph.D., M.A., F.B.S., F.L.S.) 



(Plates XXXVI. -XXXVIII.) 



Read 19th January, 1899. 



Introduction. 



iHE large collection of sections of fossil plants formed by tbe late Prof. W. C. 

 Williamson, P.E/.S., and now preserved in tbe Natural History Museum, contains a 

 considerable number of slides which he referred to Lepidostrobus. 



Owing to the fragmentary character of the remains, it has been found impossible to 

 refer with certainty any of these Lepidostrohiis slides, in which the structure is preserved, 

 to the particular vegetative organs to which they belong; although, from the association 

 of vegetative stems and strobili in the same deposit, Williamson was led to believe that 

 we know the strobilus borne by Lepidodendron brevifolium^ Will.* (the Burntisland 

 form), and probably also that of the Arran type, Lepidodendron Tf^mischianum, 

 Will.t 



In 1877 t Williamson first described as a Lepidostrobus a cone of marked individuality 

 to which, later (in 1879) §, he gave the name of Lepidostrobus insignis. Still later (in 

 1889) II he described a supposed vegetative stem to which he gave the name of Lepido- 

 dendron Spenceri, and in his last memoir " On the Organization of the Fossil Plants of 

 the Coal Measures," read in 1892% the connection between this supposed vegetative 

 stem and the previously described strobilus was established. The researches of Dr. Scott 

 have shown, however, that Lepidodendron Spencer i. Will, is but the peduncle of the 

 strobilus, and peculiarities of tlie latter have led this author to remove it from the 

 Lepidostrobi altogether, and to refer it to a new genus — that of Spencerites **. In this 

 case also, therefore, the true vegetative organs are either unknown or unidentified. 



* Williamson, W. C, " Organization of the Fossil Plants of the Coal Measures, Part III.," Phil. Trans. 1872, 

 p. 296 ; "General, Morphological, and Histological Index to the Author's Collective Memoirs on the Fossil Plants of 

 the Coal Measures," Part II. p. 102, Mem. &, Proc. Manch, Lit. & PhiL Soc. scries IV, vol. vii. 



t " General Index," Part II. p. 109. 



+ Williamson, " Organization," Part IX., Phil. Trans. 1878. 



§ Ibid., Part. X., Phil. Trans. 1880, p. 502. 



II Ibkl., Part XVI., Phil. Trans. 1889, p. 199. 



f lUd., Part XIX., Phil. Trans. 18ii:i, p. 24. 



** Scott, D. H. " On the Structure and Affinities of Fossil Plants from the Palaeozoic Rocks. II. On 

 Spencerites, a new Genus of Lycopodiaceous Cones from the Coal Measures, founded on the Lepidodendron Spenceri 

 of Williamson," PhiL Trans. P. 1898. 



SECOND SERIES. — BOTANY, \0L. V. 3 I 



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