Bd. III: 14) 
THE MESOZOIC FLORA. 
47 
Cycadophyta. 
Genus Nilssonia Brongniart. 
Nilssonia tæniopteroides n. sp. 
PI. 5; pi. 6, figs. I — 7; text-fig. ll. 
One of the most conspicuous and characteristic members of the Jurassic flora of 
Hope Bay is a species of Nilssonia. It is different from all forms hitherto known 
of that genus, and it has therefore been necessary to create a new name. 
Fronds large, very long and narrowly linear with a distinct stalk, which is at 
least 6 — 7 cm. long. Lamina very gradually tapering towards the base, more or 
less rapidly contracted upwards, and the apex obtuse. Midrib stout, the lamina at- 
tached to its upper side. Secondary veins equal, simple (or exceptionally forked), 
dense, about 1 5 — 20 in a length of a centimetre, forming a fairly wide angle with 
the midrib and distinctly arched forwards. 
The fronds of this species attained very considerable dimensions. The lower- 
most one in pi. 5, for instance, measures about 35 cm., without any signs of taper- 
ing at the broken upper end and with a breadth of only 3 cm. at most. As other 
more fragmentary specimens reach sometimes a breadth of at least 7 cm., an idea 
may be gathered of the large size of this species. 
The petiole is very stout, as is to be expected from the great length of the 
frond. Only in the specimen shown in pi. 6, fig. 4, is the whole petiole preserved, 
measuring 9.5 cm. in length and 0.3 — 0.4 cm. across on the impression. At the 
lower end of the stalk, where it was attached to the main axis, there is a distinct 
expansion, which does not, however, show any marked scar. 
In the text-fig. li r? is figured the basal portion of another leaf-stalk found close 
to the former one in the same piece of rock. It has a breadth of 0.4 — 0.5 cm. in the 
middle and a length of more than 1 1 cm., being strongly bent near the upper end, 
but there is no trace seen of a lamina. It is not quite certain, therefore, that this 
petiole is that of our Nilssonia.^ but probably this is the case, since it shows a great 
resemblance to the specimen shown in pi. 6, fig. 4. It has a similar basal expansion, 
only broader, measuring about 12 mm. on the impression, and more complete. At 
the very base of this expansion there is, marked off by means of a fine but distinct 
convex line, a crescent-shaped area, of which the lower convex outline is formed by 
the basal edge of the petiole. This area evidently represents the scar marking the 
plane of attachment to the stem. It shows some small but distinct dots forming 
a bow-shaped row nearly concentric with the upper limit of the scar. There is no 
