
TETRADYNAMIA, SILIQUOSA. 
retired banks of the Wissahickon, and on the edges of grassy- 
Janes, not unfrequent. Perennial. June, July. 
301. SISYMBRIUM. Gen. pl. 1089. ( Crucifere.) 
Silique terminated by a short terete rostrum, 
valves nearly straight, not elastic. Calix 
and corolla spreading.— Nutt. 
1. S. siliques declinate, oblong-ovate; leaves ob- 
long-lanceolate or pinnatifid, serrate, petals 
longer than the calix.—/Filld, 
Icon. FI. Dan. 984. 
Water Radish. 
From fifteen inches to three feet high. Whole plant of a 
very yellow-green. Flowers small, yellow. Leaves subject to 
be eaten by insects. On the margins of our rivers and creeks; 
and along the borders of dirty ditches, very common. Peren- 
nial. July, August. 
2. S. silique declinate, leaves pinnate; leaflets 
lanceolate, incisely serrate. L. 
S. vulgare, Pers. 
S. sylvestre, L. 
Creeping Water-cress. 
Scarcely more than a foot or fifteen inches high. Flowers 
yellow, and not unhandsome. This plant covers large patches 
of ground on the low wet margins of the Delaware, just above 
Kensington; and it has every appearance of being a native 
there. It is not improbable, however, that it has been acci- 
dentally introduced in that neighbourhood, where at least it is 
unequivocally naturalized. I have this summer found young 
leafing specimens four miles higher up the Delaware. Peren- 
nial. July. 
$02. ERYSIMUM. Gen. pl. 1090. (Crucifere.) 
Silique columnar, 4-sided. Calix closed. 
amphibium. 
vulgare. 
1. E. siliques of the spike adpressed, leaves unci- officinale. 
nate.—Willd. 
Icon. Fl. Dan. 560. 
