384 Polygonacce—Polygonum. 
P. amphibium is a perennial aquatic or semi-aquatic native 
species. When growing in water the petioles are very long 
and the stipules smooth, whilst the terrestrial form has short 
petioles and hispid stipules. The flowers are bright red. 
4. P. vaccinifoliwm.—tThis is a desirable creeping branched 
sub-shrubby species. Leaves small, oblong-ovate, acute, with 
slightly revolute margins. Flowers bright rosy red, in nume- 
rous terminal spikes towards the end of Summer. Native of 
Northern India. 
5. P. orientale—A tall annual species from 3 to 4 feet 
high. Leaves large, ovate-acuminate, pilose or nearly glabrous. 
Tlowers deep rosy purple or white, in long drooping racemes. 
Northern India and China. 
2. RHEUM. 
Perennials with usually very large radical leaves on lony 
i 
\f) 
Fig. 206. Rheum undulatum. (About 4; nat, size.) 
petioles, and an erect branched somewhat leafy inflorescence, 
