346 BRASSICACEAE 



31. BRASSICA L. CABBAGE, RAPE, TURNIP, BLACK MUSTARD. 



Annual, biennial, or perennial herbs, caulescent, with alternate leaves. Flow- 

 ers perfect, in elongate racemes or panicles. Sepals ascending, equal or the 

 outer somewhat saccate at the base. Petals yellow or white, clawed. Filaments 

 free, unappendaged. Pods elongate, linear, terete or somewhat 4-angled, with 

 an elongate-conic seedless beak, the valves 1-3-nerved; stigma truncate or 2- 

 lobed. Seeds in one row in each cell, subglobose, marginless. Cotyledons con- 

 duplicate. 



None of the leaves clasping. 



Pod slender, 4-angled, erect, appressed to the stem. 1. B. nigra. 



Pod ascending, terete, but with a strong midvein. 2. B. juncea. 

 Upper stem-leaves clasping. 



Leaves glaucous, all glabrous except the very earliest ones; petals cream-colored, 

 long-clawed. 3. B. campestris. 

 Leaves not glaucous, the basal ones distinctly hairy; petals bright yellow, short- 

 clawed. 4. B. Rapa. 



1. B. nigra (L.) Koch. Annual; stem 5-20 dm. high, branching, glabrous 

 or nearly so; lower leaves pinnatifid, with a large rounded or oval terminal lobe 

 and a few small lateral ones; uppermost leaves lanceolate or oblong, entire; 

 sepals yellowish; petals bright yellow, spatulate, 7-8 mm. long; pod 1.5-2 cm. 

 long, a little over 1 mm. thick; beak slender. BLACK MUSTARD. Waste places 

 and fields: Me. Fla. Calif. B.C.; W. Ind.; nat. from Eu. Plain Submont. 

 Ap-S. 



2. B. juncea (L.) Cosson. Annual or biennial (?); stem erect, 3-12 dm. 

 high, branched, glabrous or nearly so; lower leaves 1-1.5 dm. long, lyrate-pinnat- 

 ifid, with a large oval dentate end lobe, the upper lanceolate or linear; petals 

 yellow, 8-10 mm. long, broadly spatulate; pod 3.5-5 cm. long, 2-3 mm. thick; 

 beak 5-8 mm. long. Fields and waste places: N.S. Va. N.M. Sask.; adv. 

 or nat. from Asia. Plain Submont. Jl-S. 



3. B. campestris L. Annual or biennial; stem 3-10 dm. high, glabrous; 

 basal leaves lyrate-pinnatifid, with a large toothed end lobe; stem-leaves lanceolate, 

 entire; petals cream-colored, spatulate, 6-7 mm. long; pod 5-7 cm. long, about 

 3 mm. thick; beak about 1 cm. long. RAPE, RUTABAGA, SWEDISH TURNIPS. 

 Fields and waste places: N.S. Mont. Colo.; escaped from cultivation. Plain 



Submont. Ap-O. 



4. B. Rapa L. Annual or biennial, closely resembling the preceding, 

 but greener and more hairy, and with smaller and bright yellow flowers. TURNIP. 

 Waste places: west to Wyo. and Mont.; escaped from cultivation. Plain. Ap- 

 O. 



32. ATHYSANUS Greene. 



Small annuals, branched near the base, with toothed or pinnatifid leaves. 

 Flowers perfect, minute in elongate racemes. Sepals ovate-rounded, spread- 

 ing, equal at the base. Petals minute, linear, or wanting. Stamens subequal, 

 with slender filaments. Anthers short. Fruit orbicular, 1-celled, 3-4-ovuled, 

 but 1-seeded, wingless, covered with uncinate hairs. 



1. A. pusillus (Hook.) Greene. Delicate annual; stem branched near the 

 base, pubescent with branched hairs; leaves oblanceolate or obovate, toothed, 

 8-15 cm. long, stellate; petals white, spatulate, 1.5 mm. long, or in the later 

 flowers usually wanting; fruiting pedicels recurved, 2-3 mm. long; pod orbicular, 

 2-2.5 mm. broad, hirsute. Dry prairies and hills: Calif. -Ida. -B.C. Son. 

 Submont. F-My. 



33. THYSANOCARPUS Hook. 



Slender caulescent annuals, with alternate leaves. Flowers perfect, in slender 

 racemes. Sepals ovate, rounded, spreading. Petals spatulate, white or purplish. 

 Stamens subequal, with slender filaments. Pods orbicular, 1-celled, 1-ovuled, 

 1-seeded, indehiscent, winged, the wing often toothed on the margins like a cog- 

 wheel or perforated by round holes near the margins; style slender, but short. 

 Pubescence of simple hairs or none. 



