xiv Obituary,- — David Thomas Gwynne- Vaughan. 
The anatomical portion of the paper is an extension of the results 
communicated in his preliminary notes, illustrated by excellent drawings. 
From a purely anatomical point of view, Gwynne- Vaughan’s other 
Kew paper, ‘ On Polystely in the Genus Primula ’ (1897. 2), * s perhaps more 
important. He paid much attention to the variations of stelar structure in 
the same species and in different parts of the individual plant. He was 
able to show that gamostely is not an advanced condition due to the fusion 
of steles, but is more primitive than dialystely, and that a gamodesmic 
structure (with the bundles united, but not completed to form steles) 
probably preceded either. He followed the anatomical development of 
the seedling in gamostelic and dialystelic species with much care, and found 
different modes of transition from the original monostely to the perfect or 
imperfect polystely of the adult stem. His results marked a distinct 
advance on Van Tieghem’s interpretations, and had a direct bearing on his 
own later work on the Ferns. 
This work, as we have seen, was in full progress during the interval 
between his two tropical journeys. Publication did not begin till some 
time after his return from the Malayan expedition, when the first paper 
on the Anatomy of Solenostelic Ferns appeared, dealing with the remark- 
able New Zealand Fern, L ox soma Cunninghamii (1901. 1). He revived 
the term ‘solenostely ’ invented but afterwards discarded by Van Tieghem, 
in place of the then familiar c gamostely ’, on the ground that the latter 
term implies a fusion of steles supposed to be originally distinct ; in most 
cases this is the reverse of the truth, the solenostelic preceding the dialy- 
stelic condition, as shown by the development of the individual plant. 
The conception which lies at the root of Gwynne- Vaughan’s Fern anatomy 
thus follows directly from the results he first attained by his study of the 
Primulas. 
The solenostele is defined as a single hollow vascular cylinder, inter- 
rupted only by the departure of the leaf-traces. The conception is thus 
narrower than that of gamostely. In Jeffrey’s terminology, Gwynne- 
Vaughan’s solenostely forms ‘ a special type of amphiphloic phyllosiphony ’, 
i. e. a vascular tube with internal as well as external phloem, interrupted by 
leaf-gaps. 
The comparative rarity of solenostely is pointed out, the Ferns offering 
the chief examples. 
The detailed investigation of Loxsoma not only established an excellent 
type of solenostely, but proved interesting in other ways, especially in 
the demonstration of two kinds of protoxylem, endarch and spiral in 
the leaf-trace, exarch and scalariform in the stele. The affinity of 
the genus was regarded as closest with the Dennstaedtias, while some 
relation to Gleicheniaceae, Hymenophyllaceae, and Schizaeaceae was also 
recognized. 
