HEPTANDRIA MONOQYNIA. 353 



R. verticillatus : valves entire, all of them graniferous , racemes leaf- 

 less ; leaves lanceolate ; sheaths cylindrical. 



HAB. Wet places. June. Root large ; stem 2 feet high ; Jlower 

 iemivertieil. 



1 1 Valves toothed. 



R. acutus : valves oblong, somewhat toothed, all of them graniferous ; 

 leaves cordate oblong, acuminate, whorls leafy. 



HAB. Waste places. May. Stem 23 feet high ; lower leaves 

 large. . 



R. obtusifolius : valves dentate, one of them conspicuously granifer- 

 ous ; radical leaves ovate-cordate, obtuse ; stem somewhat scabrous. 



HAB. Woods and fields. June July. Root brown ext., yellow int. ; 

 radical leaves very large. . 



** Flowers dioecious ; valves grainless. ACETOSA. 



R. acetocella : leaves lanceolate-hastate, with the lobes spreading or 



recurved. 



HAB. Fields. May July. Stem 412 inches; plant acid. , 

 Pist. flower rare. 



TETRAGYNIA. 



181. SAURURUS. Lizard's-tail. 



S. cernuus. 



HAB. In water. July August, <2|. ; stem 18 inches 2 feet high ; 



leaves alternate, petiolate cordate, spike 3 6 inches long, white, 



calyx tubular. 



POLYGYNIA. 



182. ALISMA Water-Plantain. 



A. Plantago : leaves ovate-cordate, acute or obtuse, 9-nerved ; flow- 

 ers in a compound verticillate panicle ; fruit obtusely triangular. 



HAB. In water. July August, 1}.; leaves radical, 9-nerved; 

 petiol. ; panicles large ; Jlower white. 



, 



HEPTANDRIA. 



Ociiera. 



MONOYGYNIA 



183. TRIENTALIS. Calyx 7-leaved; corolla 7-parted, equal, flat; 

 berry dry, 1 -celled, many-seeded. 



