Sahni . — On an Australian Specimen of Clepsydropsis. 83 
and conveyed to Germany by Ludwig, was at Dresden, but Stenzel also 
examined a slice in the possession of Goeppert . 1 
Hitherto two species, namely, C. antiqua , Ung., from the Upper 
Devonian of Thuringia, and C. kirgisica, Stenz., doubtfully from the Lower 
Permian of West Siberia, have been recognized. The published descriptions 
do not reveal any differences that are clearly of specific value, but, pending 
a more detailed examination of Stenzel’s fossil, it is prudent to keep the two 
species apart. 
The most recent paper directly bearing upon the subject is Mrs. 
Osborn’s ‘ Preliminary Observations on an Australian Zygopteris \ 2 which is 
of great interest as being the first record of the Zygopterideae from outside 
of Europe and Siberia. In this paper two important points, on which there 
has been a good deal of speculation in the past , 3 have been definitely 
settled. Firstly it has been shown that the cauline xylem cylinder is of the 
A nkyropteris Grayi type, and secondly that the leaf-trace is nipped off as 
a closed ring of xylem enclosing a portion of the ‘ mixed pith * of the 
stellate axial cylinder, and that this ring subsequently becomes flattened, 
with a slight curve convex on the adaxial side (as is often the case in 
A nkyropteris). The curve finally disappears, and a slight median constric- 
tion imparts to the trace the form well known for the genus Clepsydropsis 
(see Text-fig. 2, j). There are no axillary branches. 
III. Nomenclature. 
As already mentioned, Mrs. Osborn has proposed to place the fossil 
in the genus A nkyropteris^ a perfectly natural course, considering the 
stem structure and the mode of origin of the leaf-trace. On the other 
hand, the shape finally assumed by the leaf-trace would by itself lead to 
a reference of the plant to the genus Clepsydropsis . In fact the latter course 
was at first actually adopted in the case of the Mt. Tangorin specimen, 
described below, in which the stem and the leaf-trace origin are not preserved. 
However, the combination, in the Barraba specimen, of the structural 
1 In the same year Schenk (1889, pp. 553 - 4 ; see also Schenk, 1890, pp. 46 , 156 ) figured and 
briefly described a fossil ( Rachiopteris Ludwigii , Leuckart u. Schenk) mainly agreeing with Stenzel’s 
description of C. kirgisica. The original of Schenk’s outline drawings (PI. Ill, Figs. 50 , 51 ) was in 
the Botanical Collection at Leipzig and was named by him after Ludwig, who collected it in the 
Ural steppes between Akolinsk and Semipalatinsk, and Leuckart, through whose agency it reached 
Leipzig. The ultimate sources of the two originals are so nearly identical as to leave little doubt 
that they were portions of the same specimen, yet neither Stenzel nor Schenk refers to the other’s 
paper ; on the contrary, both the authors seem to imply that their respective fossils were till then 
undescribed. There is on this point a regrettable confusion in the literature, which, in spite of 
Solms-Laubach’s (1910, p. 543 ) attempt to explain it, appears not yet to have been removed. Only 
C. kirgisica , Stenz., has been recognized by subsequent writers, although it is possible that 
C. {RachioptS) Ludwigii, Leuck. u. Schenk, may be distinct, for Schenk’s figures of the transverse 
sections show the petiolar trace in this fossil at least half as long as the petiolar diameter. 
2 Osborn (1915), pp. 727 - 8 . 
3 Bertrand (1908, 1911 b, 1911 c, 1912, 1914); Solms (1910), pp. 540 - 1 . 
G 2 
