104 M. Brongniart on the Relations of the 
over, they are dichotomous with a bifurcation which is distinct, 
and forms a very obtuse angle. A few ferns only having a sim- 
ple flabelliform frond, present a structure tolerably analogous to 
that of the leaflets of Noggerathia: such are Schizea latifolia and 
elegans, hut the general form of the leaf is very different. 
These structural characters of the leaves appear to exclude all 
real analogy of the fossil plants which we are considering with 
the two families, the Palms and Ferns. 
But there is another family very widely diffused among the 
primary creations of the vegetable kingdom, which presents a 
much more marked analogy with Noggerathia in the structure of 
its leaves ; it is that of the Cycadee. We know that the Cy- 
cadee, long since placed by botanists sometimes near the Ferns, 
sometimes the Palms, have been considered by all recent authors, 
especially since the beautiful publications of L. C. Richard and 
Du Petit Thouars, as intimately allied to the Conifere, and form- 
ing with them the remarkable group of gymnospermous dicoty- 
ledons. But if the Cycadee and Conifere are united by the 
most important points in their organization, they differ extremely 
in their general aspect, in which the Cycade@ resemble the Palms. 
Like them, the Cycadee have pinnate leaves with linear lanceo- 
late or oblong and almost spatulate leaflets. However, the struc- 
ture of these leaflets is very different in these two families. In 
Cycas they are traversed by a single median nerve ; on the con- 
trary, in Zamia, and especially in the American Zamie, each leaflet 
is traversed by slender and numerous nerves, which are of perfectly 
equal size, arise directly from the base of the leaflet, simple and 
parallel when the leaflet is lmear or oblong, slightly divergent 
and bifurcate at a very acute angle when the leaflets are obovate 
or spatulate. In short, the neuration is exactly the same as that 
of Noggerathia. The general form of these leaflets is also very 
analogous when we compare certain species of Noggerathia, such 
as NV. foliosa and spatula, with some species of American Zamie, 
as Zamia furfuracea, integrifolia and pygmea. Other species 
are further removed from the existing Cycadee by the form of 
their leaflets; but the characters of the nervation remain the 
same, and their importance is evidently much greater than that 
of the form of the leaves. Thus the Noggerathie appear to me | 
clearly to approach the Cycadee in the structure of their leaves, 
and to belong to the division of the gymnospermous dicotyledons. 
But the Cycadee and the allied families are frequently arbo- 
‘rescent plants, furnished with both male and female flowers, and 
with seed of a considerable size. May we not find portions of 
these organs in the strata in which Noggerathie occur, which 
would confirm and more accurately determine the affinities of 
- these plants ? 
