• ■■'*'.., • 



p 



PRB-CARBONIFEROUS PLANTS. 



41 



cation of Psilophyton render it probable that the little clusters of leaf-like 

 bodies from St. John which I referred to the species Annularia acuminata 

 are really spore-cases of this species. (See PI. XIX.) 



61. Psilophyton? qlabrum. Dn,— (PI. VII., Fig. 79.)— J. G. S., 

 XVm., 315.— M. D., St John, New Brunswick. 



*♦ Smooth, flattened, bifurcating stems, two lines in width, with a slender 

 woody axis." 



I regarded this species, at the time -vthen it was named, as of very doubt- 

 ful character, in so far as its aflSnities with the proper species of Psilophyton 

 are concerned. Additional specimens have not dispelled my doubts, 

 though I still retain the name to indicate a fossil not hifrequent at St. 

 John, but of uncertain nature. The specimens are smooth, flattened, 

 bifurcating stems, about two lines in width, with indications of a slender* 

 woody and vascular axis. The surface is usually quite smooth, but occa- 

 sionally marked with fine longitudinal striae. They are always flattened, 

 but from their structures must have been cylindrical and cellular with a 

 (slender axis. They resemble the larger stems of Pinnularia, but have no 

 branchlets or indications of these, nor have I found in them any indications 

 of leaves or other organs, though I have stems in my collection apparently 

 well preserved and a foot in length. If not stems of a species of Psilophy- 

 ton, they must have been roots of some plant of this genus. They much 

 resemble certain stems with a slender axis, from the Upper Silurian, 

 referred to farther on. Fig. 80 represents stems of P. robuatius and a 

 petiole of a fern, for comparison. 



Genus Arthrostioma — Dn. 

 52. Arthrostioma gracile, G. and S. N.— (PI. XIII.)— L.D., Gasp^. 



Stems elongated, cylindrical, bifurcating, and giving q/f lateral branches ; 

 irregularly furrowed or ribbed longitudinally, with circular leaf- 

 scars arranged in whorls, and bearing linear rigid leaves with 

 circular bases. Structure apparentlg cellular, with a slender 

 vascular axis ; fructification probably in cylindrical strobiles. 



The genua Cyclostigma was proposed by Haughton, in 1859,* to include 

 plants with whorls of rounded scars found in the '* old red sandstone" of 

 Kiltorcan, in Ireland. His specimens had no leaves ; but as figured, some 

 of them show indications of a vascular axis. The plant above described 



• Trans. R. Irish Academy. 



