A Drift-seed (Ipomoea tuberosa, L.). 
BY 
W. B. HEMSLEY, F.R.S., 
Principal Assistant , Herbarium , Royal Gardens , Kew . 
With Plate XXIV. 
I N most books treating of Ipomoea tuberosa it is recorded as 
a native of tropical Asia, Africa, and America ; but Mr. 
C. B. Clarke 1 has separated the Old-World plant under the 
name of I. kentrocaulos , characterised by having a much 
smaller capsule without the greatly thickened pedicel ; smaller 
elliptic-oblong sepals ; and smaller, almost glabrous, seeds. 
Whether these characters are constant the specimens are 
insufficient to determine satisfactorily ; but typical I. tuberosa 
with thickened pedicels, very broad lignified sepals, large cap- 
sule, and hairy seeds, as figured here in Plate XXIV, was early 
cultivated in English hothouses 2 , and in India, Hongkong, 
Mauritius, South Africa, and other warm countries inhabited 
by English people. In foliage and flowers there are no obvious 
differences in the dried state. 
Although this is termed here a drift-seed, it is not so in the 
sense of several of its congeners, which are common sea-shore 
1 Hooker’s Flora of British India, iv. p. 213. 
2 See Transactions of the Horticultural Society of London, i. p. 184, plate 11, 
and the Botanical Register, plate 768. 
[Annals of Botany, Vol. VI. No. XXIV, December 1892. 
