28 CRUCIFERJE. (MUSTARD FAMILY.) 



5, A. Canadensis, L. Stem stout, simple, nearly smooth above ; leaves 

 thin, downy, lanceolate, slightly toothed, sessile by a narrow base, the lowest 

 coarsely or pinnatitid-toothed ; siliqucs curved, drooping, on rough pedicels; 

 Beeds winged. (A. falcata, Miphx.) — Dry or rocky places in the upper districts. 

 May and June. — Stems 2°-3° high. Silique 2'-3' long. Flowers white. 

 Petals oblong-linear, not twice the length of the hairy calyx. 



C. A. laevigata, DC. Smooth and glaucous; stem erect; leaves linear 

 or lanceolate, entire or sparingly toothed, sagittate and clasping at the base ; 

 pedicels slmrt; petals (whitish) narrow, slightly exserted; silique elongated, 

 narrow-linear, recurved-sprcading ; seed winged. — Rocky places, North Caro- 

 lina, Tennessee, and northward. May. — Stem l°-2° high. Silique 2' -3' 

 long. 



7. SISYMBRIUM, L. Hedge-Mustard. 



Silique linear or oblong, terete or somewhat angled, with 1 -3-nerved valves. 

 Seeds in a single row in each cell, oblong, marginless. Cotyledons linear-oblong, 

 incumbent. — Herbs with simple or pinnately divided leaves. Flowers in ra> 

 cemes, small, white or yellow. 



1. S. canescens, Nutt. Pubescent and somewhat hoary ; stem simple or 

 sparingly branched; leaves bipinnatifid, with small mostly toothed lobes; ra- 

 cemes at length elongated ; silique shorter than the spreading pedicel. (Carda- 

 mine ? multifida, DC.) — Waste ground, Florida, northward and westward. 

 March and April. Q, — Stem l°-2° high. Flowers small, greenish-white. 



2. S. Thaliana, Gaud. Stem slender, branching, hairy at the base ; leaves 



hairy, toothed or entire, the lowest obovatc or oblanceolate, tufted, the others 

 small and scattered ; siliqucs linear, erect-spreading, twice as long as the pedi- 

 cels. — Bocks and sterile soil, Georgia and northward. Introduced. March 

 and April. © — Stem 4' -8' high. Flowers white. 



3. S. officinale, Scop. Stem tall (2° -3°), branching, and with the run- 

 cinate leaves pubescent; silique subulate, nearly sessile, appressed to the rachis. 

 — Waste grounds in the upper districts, and northward. Introduced. May- 

 Sept. (V) — Flowers pale yellow. 



8. WAKEA, Nutt. 



Silique linear, flattened, long-stalked, recurved; the valves 1-nerved. Seeds 

 ID a single row Ul each cell. Cotyledons oblong, flat, incumbent. — Smooth 



and civet branching annuals. Leaves entire. Flowers showy, in corymb-like 

 raceme-. Petals long clawed, white or purple. 



1. W. amplcxifolia, Nutt, Leaves oval and Blightly i petals 



oval, l.irjlit purple ; silicpie linear. — Sand bills, Florida. September. —Sum 



lo_2° high. 

 'j. W. cuneifolia, Nutt. Leaves wedge-lanceolate; petals obovate, white 



or rarely purple; silique narrow-linear. — Sand bills, Florida and (. 



September.— Stem l°-2 fl hi 



