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ARKIV FOR BOTANIK. BAND 10. n:o 14. 
Cloughtonia rugosa noy. gen. et sp. 
Frond ovate or spatulate with obtusely pointed apex and 
narrow protracted base. Margin entire. Veins bifurcating, 
radiating from the base, and the median portion of the frond. 
The median portion, except in the uppermost part, more or less 
strongly rugose. Epidermis on both sides similar, of small, rect- 
angular, thick-walled cells and without stomata. 
The fronds vary considerably in shape and size. In the 
small specimen fig. 1, pl. 1, the narrow basal portion is very long 
and protracted. Fig. 2 of the same plate shows the base of an- 
other, larger frond; here, too, the margins are, for some distance, 
nearly parallel. In the specimens pl. 1, figs. 4 and 5, the narrow 
basal part is short and abruptly cut off. All specimens agree 
in the base being broad and abruptly truncate, indicating a 
broad zone of attachment.of the frond. The apex is more or 
less pointed but not acute, and the shape varies from ovate to 
spatulate. The venation is in most specimens very indistinct 
and appears sinuous. In the median zone of the frond, more- 
over, it is concealed by the rugosity of the surface of the lamina. 
In the frond pl. 2, fig. 1, which is the specimen first discovered 
by Prof. NATHORST, however, the lateral veins are clearly seen. 
They are somewhat arched and divide repeatedly, the last bifurca- 
tion occurring near the margin. The last marginal branches are 
slightly bent forward and appear to be connected by marginal 
anastomoses — as may be seen in pl. 2, figs. 2, 3. The character- 
istic rugged aspect of the lower median portion of the frond 
appears to be due to a wrinkling of the tissues of the lamina, 
not to any kind of protuberances of the cuticle. This is 
confirmed by microscopical examination of the carbonized 
remains of the epidermis. The wrinkles have a transverse di- 
rection, and as they are crossed over by the longitudinal me- 
dian veins they appear different on the two sides of the frond, 
the veins being more marked on one side (the lower?). This 
is seen by comparing figs. 5 and 6, pl. 1., which represent im- 
pressions of the two sides of the frond, fig. 6 being probably 
the impression of the lower side. In fig. 7 which shows a por- 
tion of the same impression as fig. 6 slightly magnified, the rela- 
tion between veins and wrinkles is still more clearly seen. 
The fronds appear to have been thin but of a firm consist- 
