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 pinnatifid-toothed ; siliques curved, drooping, on rough pedicels; 

 seeds winged. (A. falcata, Michx.) 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. 



6. A. Isevigata, DC. Smooth and glaucous ; stem erect ; leaves linear 

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

 pedicels short; petals (whitish) narrow, slightly exsertcd ; silique elongated, 

 narrow-linear, recurved-spreading ; 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. @ 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 obovate or oblanceolate, tufted, the others 

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

 cels. Rocks and sterile soil, Georgia and northward. Introduced. March 

 and April. @ Stem 4'- 8' high. Flowers white. 



3. S. Oflacinale, 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. (1) Flowers pale yellow. 



8. WAREA, Nutt. 



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

 in a single row in each cell. Cotyledons oblong, flat, incumbent. Smooth 

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

 racemes. Petals long-clawed, white or purple. 



1. W. amplexifolia, Nutt. Leaves oval and slightly clasping; petals 

 oval, bright-purple ; silique linear. Sand hills, Florida. September. Stem 

 l-2 high. 



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

 or rarely purple; silique narrow-linear. Sand hills, Florida and Georgia. 

 September. Stem l-2 high. 



