xviii Obituary .—David Thomas G wynne- Vaiighan. 
work, and especially to the fine series of memoirs on the Fossil 
Osmundaceae. 
I am told that Kidston and his future colleague first met at Cambridge, 
during the British Association Meeting of 1904, and at once became 
friends. 
Their joint work began soon after while Gwynne-Vaughan was still at 
Glasgow, but their first paper was published in 1907, the year he left, and 
from that time onwards they had to arrange special meetings during vaca- 
tions, usually at Stirling. A well-known photograph shows them hard at 
work together in the study at 12 Clarendon Place. 
The series on Fossil Osmundaceae is of exceptional interest, for the 
authors trace back an existing family from recent times to the Permian, 
on sound evidence, mainly anatomical. Nothing quite like this has been 
done for any other group. There are five Parts, ranging in date from 
1907 to 1914, all published in admirable form in the Transactions of the 
Royal Society of Edinburgh. 
Part I (K. and G.-V., T907) deals with four species of Osmundites : 
O. Danlopi and Gibbiana , new species from the Jurassic of New Zealand, 
O. Dowkeri , Carr., from the Lower Eocene of Herne Bay, and O . skidega- 
tensis , Penh., from the Lower Cretaceous of the Queen Charlotte Islands. 
The first three are more or less typical members of the family ; O, Dunlopi 
approaches Todea , but was found to have a ‘ practically continuous xylem- 
ring ’ ; the other two are nearer Osnnmda. 
The Pacific species, O. skidcgate?isis, intermediate in age between the 
New Zealand and the Herne Bay fossils, showed a much more complex 
structure than either, or than any living species. The wonderful preserva- 
tion exhibited the structure to perfection, and the plant proved to have 
well-developed internal phloem, continuous through the leaf-gaps with the 
external phloem-zone. In fact O. skidegatensis comes very near the dictyo - 
stelic ancestor of the Osmundaceae, postulated by Jeffrey. Kidston and 
Gwynne-Vaughan, however, regarded the plant rather as marking the 
culminating point in the development of the family. 
In this first memoir the authors anticipated the discovery of ancestral 
types with a continuous zone, or even a solid mass of xylem, and suggested 
a common origin of the Osmundaceae with Botryopteris and Zygopteris. 
Their anticipation was soon realized ; in their second memoir (K. and 
G.-V., 1908. 1) they described two species from the Upper Permian of 
Russia, establishing the new genus Zalesskya for them. In Z . gracilis 
(Eichwald) they found a wide, continuous ring of wood, divided into two 
zones, the inner of which consisted of short and broad tracheides. In 
if. diploxylon , sp. nov., there was evidence that the xylem was solid, the 
inner zone extending to the centre of the stele. This may also have been 
the case in the former species, though there the internal tissue had entirely 
