Didissandra and Allied Genera in China and N. India. 
BY 
WILLIAM GRANT CRAIB, M.A., 
Lecturer on Forest Botany and Indian. Forest Trees 
in the University of Edinburgh. 
COLLECTIONS of herbarium specimens received here of recent 
years trom China, and more especially the large collections made 
by Mr. Geo. Forrest in S.W. China, show that in Didissandra 
as at present understood there are several very well-marked and 
easily recognised, groups. 
The genus Didissandra was created by C. B. Clarke * for the 
reception of plants which, while agreeing in general with Didy- 
mocarpus, differed from.that genus in having four fertile stamens. 
the anthers of which were coherent in pairs. And this definition 
has more or less held good since that time. No attention what- 
ever was paid to other characters, the result being, as already 
indicated, that the genus has become at the present time a collec- 
tion of sharply defined groups. The present paper is the result 
of an attempt to segregate and define those groups. 
In his original account * of the genus Clarke enumerates 
seven species. Of these six come from the Malayan region and 
one is recorded from the Himalayas, Khasia, and N. China. In 
recent years the number of species from the Malayan region has 
been considerably augmented, and I believe they constitute a 
group quite distinct from the Himalayan species and, as genera 
go in Gesneraceae, well worthy generic rank. Since then in my 
opinion Clarke included more than one genus in his Didissandra, 
it becomes necessary to delimit the genus. For this purpose | 
have taken as the type of the true Didzssandra the first species 
enumerated by Clarke, viz. D. lanuginosa. 
By taking D. lanuginosa as the type of a restricted Didissandra 
and by excluding from. it the Malayan lower level species we 
obtain a very natural series of higher level species, natives of 
the Himalayas, $.W. China, and Upper Burma. Uniformity in 
habit is accompanied by several marked characters which enable 
us to delimit the group very sharply. All are perennial. herbs 
with a thick woody rhizome, with the leaves arranged in basal 
* C. B. Clarke in DC. Monog. Phan., v, 65 (1883). 
[Notes, R.B.G., Edin., No. LV, November 1919.] 
