5 ^ 
S topes . — The Missing Link in Osmundites . 
Osmundites consisted of a portion of a rhizome and surrounding leaf-bases, 
together appearing to have been roughly circular when complete, but of which 
only a portion like a sloping quarter cut out of a round cake was preserved. 
On the waterworn surface, part of which remains, the weathered and some- 
what abraded leaf-bases are clearly visible. They vary, but measure 
roughly 4 mm. in long diameter of the surface face, representing cross- 
sections of the petioles. The specimen as a whole comprised a curved piece 
measuring about 3 x 3*5 x 1*5 cm. 
One portion of the specimen (V. 13640) and part of the slides (V. 13641 
a, b,c,d, f, g, h , z, and j) are in the Geological Department, Natural 
History Museum, kindly presented by Dr. Walcott in exchange for the 
sections cut and sent to his museum ; the other portion of the specimen 
and the other slides have been sent back to the National Museum, Melbourne, 
Australia. If desired by later workers, further sections could be obtained 
from the block in the British Museum, but this contains only leaf-bases and 
rootlets. A very short segment of the axial portion was preserved, and this 
was all cut up, yielding four slides and then running out of the specimen. Of 
these four sections the top and bottom (S 1 and S 4) each show good sections 
of the complete stele, surrounded by its single celled layer of ‘ sheath ’ cells. 
The two middle of these four sections each suffered partial demolition in the 
grinding down, so that in them the central axis, though in place, is 
incomplete. 
General Character of the Plant. 
The new Osmundites consists of a slender central solid axis surrounded 
by a crowd of leaf-bases of which the meristele is a simple curved arc bent 
with the bow outwards and the horns inwards in the usual Osmundaceous 
way. There is nothing in the leaf-bases or the leaf-traces (so far as I can 
detect) which is not absolutely typical and characteristic of the genus. The 
presence of the sclerized patches within each curve of the meristele, the 
thickened oval round the meristele, and the lateral patches in the ground 
tissue on either side of it are comparable with those described by Kidston 
and Gwynne-Vaughan for Osmundites leaf-bases. In particular, the 
diagram of the leaf base given by them in their Part V, 1914, p. 478, I 
Text-fig. 4, of ‘ Osmundites sp. from Queensland \ might almost have been 
drawn from my specimen. Compare my Text-fig with this. This feature 
can also be clearly seen in the middle of the Photo 6, PI. II. Kidston’s 
specimen, however, appeared to possess an ordinary Osmundaceous xylem 
in its main axis. 
Interspersed with the leaf-bases in the usual way also, are numerous 
small diarch roots. The new specimen, therefore, is a quite typical and charac- 
teristic Osmundites , but for its remarkable and interesting main axis. 
