No. IX. — On the Lepidodendron Harcourtii. By HENRY WITHAM, Esq., F.G.S., &c.
Read, March 19, 1832.
In the month of January, 1832, Mr. Phillips, of York, having sent me a fragment of a Lepidodendron, which had been presented to him by the Rev. C.G.V. VERNON HARCOURT, rector of Rothbury, whose zeal and activity have induced me to take the liberty of naming this fossil plant after him, I felt anxious, by means of slicing the stem, to obtain an insight into its internal structure. I had so repeatedly examined the stems of vascular cryptogamic plants without detecting any traces of organization, that I cannot refrain from mentioning the delight which I experienced when I observed a structure so perfect.
I am the more gratified as it affords me an opportunity of corroborating the opinion of so distinguished a fossil botanist as Mr. A. BRONGNIART, although founded solely upon the external markings of the peculiar plants.
To ascertain the correctness of his views, it became necessary for me
to examine into the internal structure of recent Lycopodiaceous plants,
of which, however, I have only obtained specimens of a single species.
In so far as I have discovered, the structure of this species is analogous, in most respects, to that of the stem presented to me by Mr. PHILLIPS. The specimens of this plant which I have seen, consist of subcylindrical or slightly compressed dichotomous stems. The surface is covered by a thick envelope of carbonaceous matter, presenting indistinct spiral protuberances, and beneath which are observed numerous small papillae of an elliptical form, higher than broad, and very regularly arranged in spiral series. Fig. 1 . Plate V. represents a portion of one of the stems, with some of the carbonaceous envelope remaining.
Viewed in relation to its structure, the stem presents a central axis,
which may be seen in the transverse section, Fig. 1. a. Pl. VI., and in
