28 CRUCIFER.E. (MUSTARD FAMILY.) 



2. S. Thaliana, Gaud. Stem smooth and branched above, hairy at the 

 base, 6'- 12' high, lowest leaves spatulate-ubovate, petioled, the upper lance- 

 olate, sessile, 1' long; petals white, exserted ; siliques linear, spreading, longer 

 than pedicel. (Cardamine spathulata, Midix. '.) Low ground in the upper 

 districts. Introduced. April. @. 



3. S. officinale, Scop. Stem 2 -3 high, widely branched; leaves run- 

 cinate, pubescent; petals yellow; siliqiie subulate, nearly sessile, appressed to 

 the rhachis. Waste ground in the upper districts. Introduced. (!) 



9. 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. Sept. Stem 1- 

 2 high. 



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

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

 Georgia. Sept. Stem 1- 2 high. 



10. ERYSIMUM, L. 



Silique linear, 4-angular, the valves keeled. Seeds in a single row in each 

 cell, oblong, niargiuless. Cotyledon flat, incumbent. Chiefly biennial herbs, 

 with narrow leaves, and yellow flowers. 



1. E. cheiranthoides, L. (\VORMSEED MUSTARD.) Stem erect, 

 branching above, closely pubescent; leaves thin, lanceolate, acute, entire or 

 slightly toothed, roughish; flowers small; silique ascending, rather longer 

 than the slender pedicel, the angles rounded. North Carolina (Curtis). 

 July. Stem l-2 high. Silique 8' - 10' long. 



11. HESPERIS, L. ROCKET. 



Silique nearly terete. Seeds oblong-triquetrous. Cotyledons incumbent 

 Petals obovate or linear. Stigmas erect. Chiefly annuals or biennials. 



1. H. matronalis, L. Stem tall, simple, pubescent; leaves oblong, 

 roughish, denticulate ; petals large purple. North Carolina. Escaped from 

 cultivation. 



12. SINAPIS, L. MUSTARD. 



Silique terete or 4-angled, prolonged into an empty or 1 -seeded beak, the 

 valves 1-5-nerved. Seed globose, in a single row. Cotyledons incumbent, 

 folded around the radical. Erect branching annual or biennial herbs, with 

 coarse pinnatifid leaves, and yellow flowers. All introduced. 



1. S. nigra, L. (BLACK MUSTARD.) Siliques smooth, appressed to the 

 rachis ; beak short ; seed dark brown. Grain-fields. 



