0.7-1 mm. broad; style usually slender, less than 1 mm. long; seeds in 1 row 

 in each cell, 0.6-1.5 mm. long, broadly winged above. A. ovata of Woot. & Standi. 

 In wet meadows and water in and about springs, seepage areas, stream beds 

 and damp woods in N. M. (widespread in nits.) and Ariz. (Apache and Coconino 

 COS.), May-Aug.; Anticosti to Yuk., s. to Pa. or occasionally n.w. Ga., Mo., 

 Kan., N.M., Ariz, and Calif.; Euras. 



2. Arabis divaricarpa A. Nels. 



Stem erect, 2-9 dm, tall, simple or branched, sparingly appressed-pubescent 

 at base with forked hairs; rosette leaves narrowly oblanceolate to oblanceolate- 

 spatulate, 2-6 cm. long, acute, usually dentate, minutely stellate-pubescent; 

 cauline leaves narrowly oblong to linear-lanceolate, strongly ascending, entire 

 or subentire, auriculate or sagittate at base, mostly glabrous; flowers in loose 

 racemes; pedicels soon divergent, minutely stellate-pubescent or glabrous; petals 

 pink or purplish to rarely white, oblanceolate-spatulate, 5-8 mm. long; siliques 

 glabrous, the lowest and mature ones loosely ascending to divergent, 2.5-9 cm. 

 long, 1.2-3 mm. broad, with style 0.2-0.7 mm. long; seeds in 2 rows in each cell, 

 1-1.5 mm. in diameter, narrowly winged. 



In wet mt. meadows and seepage areas, about rocks and in sandy soils in N.M. 

 (Taos Co.), May-Aug.; Gaspe Pen. to Man. and Yuk., s. to N.Y., O., Mich., Wise, 

 la.. Neb., N.M. and Calif. 



3. Arabis Dnimmondii Gray. 



Stem erect, simple or branched, often glaucous, glabrous throughout or rarely 

 appressed-pubescent at base; radical leaves to 9 cm. long, glabrous or merely with 

 ciliate petioles; flowers erect or strongly ascending; pedicels glabrous; petals 

 5-10 mm. long; siliques suberect or subappressed, flattish, 4-10 cm. long, 1.5-3.3 

 mm. broad; seeds in 2 rows, about 1 mm. in diameter. A. oxyphylla Greene. 



In moist or wet soil in mt. meadows and along streams in N. M. (Colfax, Rio 

 Arriba, San Miguel and Taos cos.) and Ariz. (Apache and Coconino cos.), 

 May-Sept.; Lab. to Alta. and B.C., s. to Del., O., Ind., 111., la., N.M., Ariz, and 

 Calif. 



3. Sibara Greene 



Eleven species, primarily of southwestern United States and Mexico. 

 1. Sibara virginica (L.) Roll. 



Annual herb; stems arising from rosette of basal leaves, erect or decumbent, 

 usually hirsute toward base, 1-3 dm. tall; leaves pinnatifid with narrow lateral 

 segments, terminal lobe somewhat broader; cauline leaves petiolate, not auriculate; 

 flowers small and inconspicuous; petals white to faintly pinkish, oblanceolate to 

 narrowly oblong, 1.5-3 mm. long; pedicels divaricately ascending, short, mostly 

 less than 4 mm. long; siliques narrowly oblong to linear, flattened parallel to 

 septum, obtuse above and below, 15-25 mm. long, 1.5-2 mm. wide, glabrous; 

 seeds nearly orbicular, flattened, narrowly winged. 



Old fields, on mud along sloughs and streams, roadsides and open areas, Okla. 

 {Waterfall) s., cen. and e. Tex., Mar .-Apr.; s. Calif, and Okla. to O., Va. and Fla. 



4. Sisymbrium L. 



About 90 species, mainly in Eurasia, the Mediterranean region and temperate 

 Africa, North America and South America. 



1. Sisymbrium altissimum L. Tumble-mustard. Fig. 468. 



Annual; stems loosely branched above, to 1.5 m. tall, hirsute toward base with 

 large spreading simple trichomes; lower leaves petiolate, hirsute, pinnately lobed, 



965 



