84 
T. G. HALLE, 
(Schwed. Südpolar-Exp. 
conveniently large one; but it will no doubt be possible, in the future, to remove 
from it many species of which the fructifications have been found or which, for 
some other reason, can be referred to a better characterized genus. 
Elatocladus heterophylla n. sp. 
PI. 8, figs. 12 — 14, 17 — 25; text-fig. 18. 
Under the name Elatocladus heterophylla have been grouped here a great num- 
ber of specimens which cannot be referred to any particular genus but which seem 
to form a rather characteristic type. 
Branching more or less dense; ultimate branchlets showing a tendency towards 
a distichous arrangement. Shoots of two different types, the one showing a radial, 
the other a dorsiventral habit. The leaves in the former type adpressed to the axis, 
in a regular spiral round the stem, short, thick, falcate; those of the dorsiventral 
shoots spread out to two sides, at a wide angle to the rachis, flattened, longer and 
less falcate. 
There is a remarkable variation in the shape of the leaves. Some of the 
branches are rather thick, measuring, with the leaves, 5 — 6 mm. in breadth on the 
impression. On such thick branches the leaves are exceptionally broad, ovate to 
triangular (text-fig. 18 U). The more slender shoots are dimorphic; one type may 
pass over into the other within the same shoot. In the radially constructed shoots, 
the leaves are placed very densely in spiral, are directed upwards and adpressed to 
the stem, which is thus quite concealed. They vary much in shape but they are 
mostly more or less lanceolate, thick and falcate. In the dorsiventral shoots, the 
leaves are spread out to two sides, thus affecting a distichous arrangement (text-fig. 
18 a). The leaves of this type of shoot are also somewhat less falcate, and thinner 
than those of the radial shoots. They are narrowly linear and sharply acute. A 
midrib is sometimes faintly visible in the leaves of both the dorsiventral and the 
radial shoots. When both types of shoots are found in one and the same specimen, 
the dorsiventral one is often expressed in the ultimate branchlets only, and often 
the latter are dimorphic, too, their lower portion being constructed radially, the upper 
dorsiventrally. It is possible, however, that this is quite accidental. In the specimen 
shown in pi. 8, fig. 25, there are at least three successive generations of shoots with 
a dorsiventral habit. 
The thickest branches preserved of this species show a certain resemblance to 
those described above under the name Pagiophyllmn cfr. Eheerianum Sap. It is 
possible that the specimen drawn in text-fig. 18 should be referred to the latter 
species; and it is also possible that this species only represents thicker branches of the 
