﻿1861.] 



BUSTBTTRY FOSSIL PLANTS, NAGPUR. 



337 



but unfortunately their origin relatively to the sheaths is obscure ; 

 for they spring- from what appear to be the old stems, on which I 

 can find no sheaths remaining. They are inserted on the stem with 

 a distinct articulation, as in Equisetum and Calamites ; but their 

 insertion appears to be exactly on the articulation of the stem, and 

 not below it. In the P. ramosa and P. Brongniartiana, the origin 

 of the branches is unequivocal ; and, though less evident, it is pro- 

 bably the same in this plant. I think, with McCoy, that this cha- 

 racter decidedly removes PhyUotheca from any near affinity with 

 Equisetum, as one of the especial and most peculiar characters of 

 the latter genus is the origin of the branches from beloiv the sheaths. 



Some further light is thrown on this question by a specimen*, from 

 SilewacM near Nagpiir, of what appears to be an old stem of a small 

 PlujUotheca; the arrangement of the ridges and furrows being such 

 as is usual in this genus, and not such as prevails in Equisetum and 

 Calamites. Here there is a scar, doubtless of a branch, seated exactly 

 on one of the articulations, and perfectly similar, except in its small 

 size, to what we see in Calamites ramosus, Ad. Br. No trace of a 

 sheath remains. 



Some of the flattened stems, which I suppose to belong to this 

 PhyUotheca, are above an inch broad, strongly and coarsely furrowed. 

 As they are pressed quite flat, without being crushed or distorted, we 

 must suppose either that they were of a soft and herbaceous sub- 

 stance, or that the wood had entirely decayed before they were 

 fossilized, leaving only a tube of bark. 



It is not improbable that the remains of PhyUotheca in this Nag- 

 pur collection may belong to more than one species, as the great 

 difference in the fineness or coarseness of the furrows on stems of 

 about the same diameter may seem to indicate ; but I cannot satisfy 

 myself as to the distinctions. 



Our materials being still so incomplete, I feel by no means sure 

 that further discoveries may not prove this Indian PhyUotheca to be 

 identical with one or other of the Australian species. Yet, as it 

 does not exactly agree with the description of any of them, and as 

 there is & prima facie probability that plants from such distant coun- 

 tries are not the same, I will provisionally name this one PhyUotheca 

 Indica. 



Its characters may be given thus : — 



Stem branched, furrowed; sheaths lax, somewhat bell-shaped, 

 distinctly striated ; leaves narrow linear, with a strong and distinct 

 midrib, widely spreading and often recurved, nearly twice as long as 

 the sheaths. 



The original PhyUotheca australis, Brongniart, and the P. 7*amosa, 

 McCoy (according to the descriptions), differ from this in having the 

 stem smooth or slightly striated, not furrowed, and the sheaths fitting 

 closely to the stem ; P. australis further in its simple stem, and 

 leaves without a midrib. P. Hooheri, McCoy,which of the described 

 species comes nearest to our Indian one, appears to have much larger 

 sheaths and longer leaves, as well as a simple stem. 



* See PL X. fig. (>. 



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