BRASSICACEAE. 161 



23. ARABIS L. 



Annual or perennial, glabrous or pubescent herbs with 

 entire lobed or pinnatifid leaves and white or purple 

 flowers. Siliques linear, elongated, compressed, with 

 smooth or keeled mostly 1 -nerved valves, not elastic, 

 dehiscent at maturity. Stigma nearly entire or 2-lobed. 

 Seeds in 1 or 2 rows in each cell, flattened, winged or 

 wingless. Cotyledons accumbent. 



Leaves deeply pinnatifid, glabrate. 1. A. virginica. 



Leaves sparingly toothed or entire. 



Pubescent throughout. 2. A. repanda. 



Pubescent only at base; cauline leaves glabrous 



and glaucous. 3. A. glabra. 



1. A. virginica (L.) Trelease. Annual or rarely biennial, glabrate; 

 stems ascending or decumbent, 1.5-3 dm. high; leaves oblong, nar- 

 row, deeply pinnatifid, 2.5-7 cm. long, the lower petioled, the upper 

 nearly sessile; pedicels spreading or ascending, 4 mm. long in fruit; 

 flowers very small, white; pods linear, ascending, 16-24 mm. long, 

 about 2 mm. broad; seeds in 1 row in each cell, nearly as broad as 

 the pod, orbicular, wing-margined. {A. ludoviciana C. A. Meyer.) 



Inglewood in low ground. Our plants have the leaves often 

 merely dentate. March. 



_ 2. A. repanda Wats. Biennial; stem stout, branching, 3 dm. 

 high or more, pubescent throughout with mostly stellate hairs, 

 usually longer and simple at base; leaves narrowly obovate to 

 oblanceolate, 3-10 cm. long, sparingly toothed or nearly entire, 

 those of the stem narrowed to a winged petiole, acute or obtuse; 

 flowers white, small; petals narrow, 4 mm. long, slightly exceeding 

 the calyx; pods recurved-spreading, faintly 1-nerved at the base, 

 seeds elliptic, broadly winged. 



Occasional in the upper portions of the pine belt in the San 

 Gabriel and San Bernardino Mountains. 



3. A. glabra (L.) Bernh. Biennial; erect, pubescent below, 

 glabrous and glaucous above, simple or somewhat branched, 5-10 

 dm. high; basal leaves petioled, 5-15 cm. long, oblanceolate or 

 oblong, dentate or sometimes lyrate, pubescent with simple hairs, 

 those of the stem with sagittate base, glabrous, entire or the lower 

 dentate, 5-10 cm. long, lanceolate or oblong, acutish; flowers yellow- 

 ish white, 4 mm. broad; pedicels 4-10 mm. long, erect; pods nar- 

 rowly linear, 5-7 cm. long, 1 mm. wide, erect and appressed; seeds 

 in 2 rows in each cell, marginless; style none. {A. perfoliata Lam.) 



Frequent in the foothills throughout our range. 



24. CHEIRANTHUS L. Wallflower. 

 Ours biennial or perennial more or less pubescent 

 herbs, with simple entire or toothed leaves. Flowers 

 mostly yellow. Siliques elongated, linear, 4-angled; 



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