On Sigillaria Brardii and its Variations. 243 
Sigillaria Brardit passes, we find on the upper portion of 
this example the typical form of Sigillaria Brardii, as figured 
by Brongniart in 1822 under the name of Clathraria Brardii, 
and which was subsequently reproduced in the “ Histoire” under 
the name of Sigillaria Brarditi. The leaf-cushion is elevated, 
transversely rhomboidal, the upper and lower margin rounded 
or slightly flattened, and the lateral angles are produced with 
a sharp point. Its surface bears a few irregular longitudinal 
lines. Somewhat near its upper margin is placed the 
rhomboidal leaf-scar, whose upper margin has a distinct 
notch with slightly convex sides; the lower margin is 
rounded, with concave sides; the lateral angles are 
prominent; cicatricules three, the central transversely 
elongate, and placed slightly above the middle of the scar, 
the two lateral, lunate, oblique (Fig. 1a). 
Passing farther down the stem a very short space, the 
leaf-scars assume the condition of the Sigillaria rhomboidea, 
Brongt. (Fig. 1b). Here the cushion has no appreciable 
elevation, still its presence is indicated by a transverse furrow 
above the leaf-scar, from the extremities of which lines extend 
dividing the bark into faint hexagonal areas, somewhere in 
the upper portion of which is placed the leaf-scar. The 
surface of the bark in this form possesses the shagreen 
ornamentation, which is less pronounced in the neighbour- 
hood of the leaf-scar. The lateral angles of the leaf-scar are 
slightly less prominent than in Fig. 1a. 
The last form to which it is necessary to refer on 
this specimen is shown at Fig. lc. Here all trace or 
indication of the leaf-cushion has disappeared, and the true 
Leiodermarian form of the plant is assumed, with the 
characteristic shagreen marking of the outer surface of 
the bark. This part of the specimen is the Sigillaria 
denudata, Goppert.t 
? Sterzel separates the Rothliegendes “‘denudata” from the Carboniferous 
‘‘denudata,” which latter he distinguishes as var. carbonica, as there has 
been, according to this writer, no true S. Brardii found in the Permian. 
This does not appear to be suflicient reason for separating specimens which 
are otherwise the same. S. Brardii has, however, been figured from the 
Rothliegenden of Thuringia by Potonié. 
