66 CRUCIFER.E. (MUSTARD FAMILY.) 



1. ARABIS proper. Seeds in one row in 'each cell, orbicular or nearly so, 

 more or less wing-margined ; cotyledons strictly accumbent. 



* Low, chiefly biennials, diffuse or spreading from the base. 



1. A. Ludoviciana, Meyer. Nearly glabrous, often annual ; leaves all 

 piunately parted into oblong or linear few-toothed or entire divisions, those of 

 the lower leaves numerous; pedicels very short; flowers small, white ; pods 

 rather broadly linear, spreading, flat; seeds winged. Open grounds, Va. to 

 Mo., and southward. 



* * Erect and simple leafy-stemmed biennials, with simple leaves, white or 



whitish Jlowers, narrow but flattened ascending or erect pods, and nearly 

 wingless seeds. 



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

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

 partly clasping by the heart-shaped base; petals (bright white, 4" long) twice 

 the length of the calyx ; pedicels slcmfcr, spreading ; pods spreading or ascend- 

 ing, tipped with a distinct style. Peuu. to central Ohio and southward ; Minn. 

 April, May. 



3. A. hirstlta, Scop. Rough-hairy, sometimes smoothish, strictly erect 

 (1 -2 high) ; stem-leaves oblong or lanceolate, entire or toothed, partly clasp- 

 ing by a somewhat arrow-shaped or heart-shaped base; petals (greenish-white) 

 small, but longer than the calyx : pedicels and pods strictly upright ; style 

 scarcely any ; immature seeds somewhat 2-rowed. Rocks, common, especially 

 northward. May, June. (Eu.) 



* * * Erect and simple leaf y-stemmed biennials (1 -3 high), with small whitish 



Jlowers, recurved-spreading or pendulous Jlat pods (3-4' long), and broadly 

 n-inged seeds, their stalks adherent to the partition ; root-leaves rarely lyrate. 



4 A. IcBVigata, Poir. Smooth and glaucous, upright ; stem-leaves partly 

 clasping by the arrow-shaped base, lanceolate or linear, sparingly cut-toothed or 

 entire ; petals scarcely longer than the calyx ; pods long and narrow, recurved- 

 spreading on ascending or merely spreading pedicels. Rocky places, Maine 

 to Minn, and southward. May. 



5. A. Canad6nsis, L. (SICKLE-POD.) Stem upright, smooth above; 

 stem-leaves pubescent, /><.n>t/td at both ends, oblong-lanceolate, sessile, the lower 

 toothed; petals twice the length of the calyx, oblong-linear ; pods very j/at, 

 scythe-shaped, hanging on rough-hairy pedicels (2" wide). Woods and ravines ; 

 not rare, especially westward. June -Aug. 



2. TURRlTIS. Seeds not so broad as the partition, in two more or less 

 distinct rows in each cell, at least when young ; strict and very leafy- 

 stemmed biennials ; cauline leaves partly clasping by a sagittate base. (Our 

 species very glabrous, except the mostly hirsute base of the stem and the lower 

 leaves.) 



6. A. perfoliata, Lam. (TOWER MUSTARD.) Tall (2-4 high), 

 glaucous ; stem-leaves oblong or ovate-lanceolate, entire ; petals yellowish- 

 white, little longer than the calyx ; pods very narrow (3' long) and pedicels 

 strictly erect ; seeds marginless ; cotyledons often oblique. Rocks and fields, 

 N. Eng. to Minn, (rare), north and westward. (Eu.) 



