TETRADYNAMIA. STLIQUOSA. 65 
Leaves entire, except in the commonest species 7% 
Bursa pastoris, in which the radical ones are pinnatifid, 
‘and the silicle moreover triangular and without margin; . 
this was the Capselia of Cesalpinius, and ought perhaps 
to be separated from this genus. In the other species the 
capsule varies in form, and the cells are also sometimes 
I-seeded, consequently there is no precision in the arti- 
ficial character, though there is something in the habit or 
mode of vegetation which appears to distinguish a Thlaspi. 
Species. 1. 7. arvense. A common weed around De- 
troit, (Michigan Territory.) 2. alliaceum. ‘This species 
sometimes occurs in fields of grain or flax, in such situa- 
tions I have observed it in the state of Ohio. 3. * tubero- 
stm. Silicle suborbiculate, short and compressed; leaves 
rhomboid-ovate, obsoletely toothed, smooth, and sessile, 
radical ones upon long petioles; stem pubescent, very 
short and simple; root tuberous and fibrous. Has. In 
Western Pennsylvania. Flowering in April and May. 
Not more than 4 or 5 inches high; flowers rather, large, 
like those ofan Arabis, rosaceous, 4. Bursa pastoris. 
Principally an European genus. 
456. LUNARIA. L. (Moonwort.) 
_ Silicle entire, elliptic, flat and pedicellate; 
valves flat, equal with the parallel dissepiment. 
Two of the leaves of the calix saceate at the 
base and coloured. — Se ae 
Leaves simple, the lower ones often opposite. Silicle - 
very large. 
Species. 1. LL. anmia. Beginning to be naturalized | 
in several localities around Philadelphia; as near Gray’s . 
Ferry, &c. accompanying Chelidonium majus, 
An European geaus, its natural limits as yet confined : 
to 2 species: ee 
ee 
Orver Il.—SILIQUOSA. 
457. DENTARIA. L. (Toothwort.) 
Silique springing open elastically and the. 
valves *nerveless” and revolute. Dissepiment 
partly fungose. Stigma emarginate. Calta lon- . 
_ gitudinally connivent. ange 
