36 CRUCIFER.E. (MUSTARD FAMILY.) 



1. S. officinXle, Scop. (Hedge Mustard.) Leaves runcinate; flow- 

 ers very small, pale yellow ; pods close pressed to the stem, awl-shaped, scarcely 

 stalked. Q) — Waste places. May -Sept. — An unsightly, branched weed, 

 2° -3° high. (Nat. from Eu.) 



2. §. ThaliAnum, Gaud. (Mouse-ear Cress.) Leaves obovate or oblong, 

 entire or barely toothed ; flowers white ; pods linear, somewhat 4-sided, longer 

 than the slender spreading pedicels. ©—Old fields and rocks, Massachusetts 

 to Kentucky, &c. April, May. — A span high, slender, branched, hairy at the 

 base. (Nat. from Eu.) 



3. S. caneSCCMS, Nutt. (Tansy Mustard.) Leaves 2-pinnatifid, the 

 divisions small and toothed ; flowers whitish or yellowish, very small ; pods in 

 long racemes, oblong or rather club-shaped, not longer than the spreading pedi- 

 cels ; seeds irregularly in 2 rows in each cell. ® — Penn. and Ohio to Wiscon- 

 sin, and southward and westward. — Slender, 1° high, often hoary-pubescent. 



11. SIN APIS, Tourn. Mustard. 



Pod nearly terete, with a stout beak (which is either empty or 1-seeded) ; the 

 valves 3-5- (rarely 1-) nerved. Seeds globose, one-rowed. Cotyledons incum- 

 bent, folded around the radicle. Calyx open. — Annuals or biennials, with yel- 

 low flowers. Lower leaves lyrate, incised, or pinnatifid. (Greek name SiVairt, 

 which is said to come from the Celtic nap, a turnip.) 



1. S. alba, L. (White Mustard.) Pods bristly, turgid, on spreading 

 pedicels, shorter than the sword-shaped one-seeded beak ; leaves all pinnatifid. — 

 (Cult, and adv. from Eu.) 



2. S. arvensis, L. (Field Mustard. Charlock.) Pods smooth, knot- 

 ty, about thrice the length of the conical 2-edged usually empty beak ; upper leaves 

 merely toothed. — A noxious weed in cultivated fields, New York and Wiscon- 

 sin. (Adv. from Eu.) 



3. S. nigra, L. (Black Mustard.) Pods smooth, 4-cornered (the valves 

 l-nerved only), oppressed, tipped with a slender persistent style (rather than beak) ; 

 leaves lyrate or lobed, the upper narrow and entire. — Fields and waste places. 

 The acrid seeds furnish the mustard of our tables, &c. (Adv. from Eu.) 



12. DRAB A, L. Whitlow-Grass. 



Pouch oval, oblong, or even linear, flat ; the valves plane or slightly convex, 

 1-3-nerved: partition broad. Seeds several or numerous, in 2 rows in each 

 cell, marginless. Cotyledons accumbent. Calyx equal. Filaments not toothed. 

 — Low herbs, with entire or toothed leaves, and white or yellow flowers. Pu- 

 bescence mostly stellate. (Name from 8pa|3ij, acrid, in allusion to the pungency 

 of the leaves.) 



§ 1. DRABA, DC. — Petals undivided. 



# Perennial, tufted, leafy-stemmed: flowers white : pods twisted when ripe. 

 1. I>. ramosiSSima, Desv. Diffusely much branched (5'- 8' high), 

 pubescent ; leaves laciniate-toothed, linear-lanceolate, the lower oblanceolate ; ra- 



