14 
T. G. HALLE, 
(Schwed. Südpolar-Exp. 
Cladophlebis antarctica Nath. in sched. n. sp. 
PI. I, figs. 15—23, 24?; pl. 3, fig. 6?. 
Before I undertook the describing of the Antarctic Jurassic flora. Prof. Nathorst 
had recognized, in one of the Cladophlebis-îorms, a new type which he named pro- 
visionally C. antai'ctica. The species is represented by quite a number of specimens 
in the collection and has evidently been a common one at the locality. 
Fronds fairly large, measuring at least 20 cm. across at the base. Rachis very 
slender as compared with the size of the frond. Pinnæ long, linear, opposite, 
attached at an open angle, the lower ones reflexed(?). Pinnules separate, attached 
by the whole of the base, lanceolate or linear, slightly falcate, gradually tapered to 
the pointed apex. Margin distinctly and often deeply dentate in the upper part or 
down to the base. Venation of the Ciadophlebis-\.y\)e\ secondary veins dividing 
only once, the two branches forming a comparatively open angle to each other. 
Fructification unknown. 
This species is well characterized by the slender rachis and the open, spreading 
habit of the frond and by the very long pinnae, of which the basal ones appear to 
be reflexed (figs. 15,21). (The latter feature may possibly be accidental.) The pin- 
nules are narrow and rather small as compared with the size of the pinnæ. The 
dentation is mostly sharp, the teeth are directed forwards. A characteristic feature 
of the venation is the unusually open angle formed by the branches of the secon- 
dary veins. 
This type of frond belongs to the group of Cladophlebis denticulata (Brgn.). 
It seems possible, however, to keep the present type separated from other fronds 
referred to this widely distributed species; and it is certainly the best way to attempt 
to reduce such large collective species, whenever that can be done by separating 
distinct smaller species. Though the forms in question occur in numerous speci- 
mens in the collection there is never any difficulty in distinguishing the fronds 
named here C. antarctica from those of typical C. denticidata. Of other forms of 
the C. dciiticulata-gvowp, Aspidiiim {Cladophlebis) Oerstcdi Heer (1882, p. 30; pl. 34) 
• bears the greatest resemblance to the Antarctic species. The resemblance is indeed 
so great that I have been in some doubt whether the latter form should not be in- 
cluded in Cladophlebis Oerstedi. But the great difference in age of the beds from 
which the two species are derived makes it seem the safest plan to keep them se- 
parated. C. Oerstedi comes from the Atane Beds of Greenland, of Upper Creta- 
ceous age and with a rich flora of Dicotyledons. There also appear to be some 
differences between the two forms. C. Oerstedi has not quite the same open and 
spreading habit of the frond as C. antarctica; and the pinnæ appear to be shorter 
