Chapter C: BURSA-PASTORIS, Moench. Root-leaves clustered, pinnatifid or toothed;

stem-leaves arrow-shaped, sessile.--Waste places; the commonest of weeds. April--Sept. (Nat. from Eu.)

19. THLASPI, Tourn. PENNYCRESS.

Pod orbicular, obovate, or obcordate, flattened contrary to the narrow partition, the midrib or keel of the boat-shaped valves extended into a wing. Seeds 2--8 in each cell. Cotyledons accumbent. Petals equal.--Low plants, with root-leaves undivided, stem-leaves arrow-shaped and clasping, and small white or purplish flowers. (Ancient Greek name, from [Greek: thla/o], _to crush_, from the flattened pod.)

T. ARVENSE, L. (FIELD P. or MITHRIDATE MUSTARD.) A smooth annual, with broadly winged pod 1/2' in diameter, several seeded, deeply notched at top; style minute.--Waste places; rarely naturalized. (Nat. from Eu.)

20. LEPIDIUM, Tourn. PEPPERWORT. PEPPERGRASS.

Pod roundish, much flattened contrary to the narrow partition; the valves boat-shaped and keeled. Seeds solitary in each cell, pendulous. Cotyledons incumbent, or in n. 1 accumbent! Flowers small, white or greenish. (Name from [Greek: lepi/dion], _a little scale_, alluding to the small flat pods.)--Ours are annuals or biennials, except the last.

[*] _Leaves all with a tapering base, the upper linear or lanceolate and entire, the lower and often the middle ones incised or pinnatifid; pods orbicular or oval, with a small notch at the top; the style minute or none; stamens only 2._

1. L. Virginicum, L. (WILD PEPPERGRASS.) _Cotyledons accumbent_ and seed minutely margined; _pod marginless_ or obscurely margined at the top; petals present, except in some of the later flowers.--June--Sept. A common roadside weed, which has immigrated from farther south.

2. L. intermedium, Gray. _Cotyledons incumbent_ as in the following; _pod minutely wing-margined at the top_; petals usually minute or wanting; otherwise nearly as in n. 1.--Dry places, from western N. Y. and N. Ill., north and westward.

L. RUDERALE, L. More diffuse, the smaller and oval _pods and the seeds marginless; petals always wanting_.--Roadsides, near Boston, Philadelphia, etc.; not common. (Adv. from Eu.)

[*][*] _Stem-leaves with a sagittate partly clasping base, rather crowded._

L. CAMPESTRE, Br. Minutely _soft downy_; leaves arrow-shaped, somewhat toothed; _pods ovate, winged_, rough, the style longer than the narrow notch.--Old fields, Mass. and N. Y. to Va.; rare. (Nat. from Eu.)