CRUCIFER-E. (MUSTARD FAMILY.) 27 



5. LEAVENWORTHIA, Torr. 



Siliquc oblong or oblong-linear, compressed, often contracted between the 

 seeds. Seeds in a single row in each cell, orbicular, flat, winged. Embryo 

 straight or nearly so. — Small annual or biennial herbs, with short 1 -few-flow- 

 ered stems, pinnatifid leaves, and yellow, white, or purplish flowers, on elongated 

 pedicels. 



1. L. aurea, Torr. Leaves mostly radical, with 4-8 oblong toothed lobes, 

 the terminal one larger and rounded; raceme at length 4- 10-flowered; style 

 manifest ; embryo straight. — On flat rocks in the upper districts of Alabama 

 and westward. — Plant 2' - 6' high. Flowers yellow. 



2. L. Michauxii, Torr. Leaves as in No. 1 ; flowers mostly solitary, on 

 radical peduncles ; style almost none ; embryo slightly curved. (Canlamine uni- 

 flora, Michx.) — Rocks, Alabama and Tennessee. — Flowers purplish or white. 



6. ARABIS, L. 



Silique elongated, linear, flattened ; valves 1 -nerved. Seeds numerous, in a 

 single row in each cell, roundish, usually winged or margined. Cotyledons ac- 

 cumbent. — Chiefly annual or biennial herbs. Radical leaves mostly pinnatifid ; 

 those of the stem sessile and often cordate or sagittate at the base. Flowers 

 white or rose-colored, in terminal racemes. 



1. A. hirsuta, Scop. Rough-hairy; stems mostly simple, erect, rigid, 

 very leafy ; radical leaves oblanceolate, obtuse, mostly entire; those of the stem 

 lanceolate or oblong, clasping, sparingly toothed; silique pedicelled, narrow- 

 linear, erect, pointed with the sessile stigma ; seeds narrow-margined. — Rocky or 

 sterile soil, Tennessee and northward. May. OP — Stems l°-2° high, often 

 several from one root. Leaves £'-1' long. Flowers small, the greenish- white 

 petals rather longer than the calyx. 



2. A. patens, Sulliv. Downy with spreading hairs, erect (1°- 2° high) ; 

 stem-leaves oblong-ovate, acutish, coarsely toothed or the uppermost entire, half- 

 clasping by the heart-shaped base; petals (bright-white) twice the length of the 

 calyx ; pedicels slender, spreading ; silique slender and curving upward, tipped 

 with a distinct style. — Rocky banks near Nashville, Tennessee, and northward. 

 May. — Siliquc 1 ^'-2' long. 



3. A. dentata, Torr. & Gray. Pubescent and roughish ; stems slender, 

 diffusely branched, erect or ascending ; leaves obtuse, unequally and sharply 

 toothed, the lowest (2' -5' long) oblong-obovate, tapering into a slender petiole; 

 the others smaller, oblong, clasping and auriculate at the base ; racemes at length 

 elongated; siliques scattered, narrow-linear, widely spreading, on short pedicels ; 

 petals whitish, scarcely exceeding the calyx. — Tennessee and northward. May. 

 — Plant about 1° high. Silique 1' long. 



4. A. lyrata, L. Stem smooth, branching from the base ; radical leaves 

 tufted, pinnatifid, ciliate, those of the stem linear or lanceolate and entire; siliquo 

 pedicelled, very narrow, erect-spreading, pointed with the short style ; seeds with- 

 out margins. — Mountains of North Carolina and northward, April -June. — 

 Stems 4'- 10' high. Flowers white, the petals twice the length of the calyx. 



