186 CRUCIFERAE. 



Vicinity of the ocean along the California const. 



8. ARABIS L. Rock Cress. 



Ours ereci and tall annuals or biennials, ot caespitose perennials. Flowers 

 rose-purple, white or yellowish white. Sepals greenish or purplish, erect and 

 equal, or the lateral pair slightly saccate a1 base. Petals obovate or spatulate, 



with narrow claw and ll.'it blade, commonly much exceeding the sepals. Pod 

 flattened parallel to tlie partition, the valves more or less 1-nerved. Seeds 

 more or less winged; cotyledons accumbent, or in one species partially incum- 

 bent. (Name from the land Arabia.) 



Leaves all pinnately parted; plants decumbently branching from the base; flowers small, 



white 1. A. virginica. 



Leaves entire, toothed or only the radical pinnatifid. 

 Tall biennials with white flowers; sepals greenish. 



Glaucous; glabrous except at the base 2. A. glabra. 



Not glaucous; hirsute throughout 3. A. hirsuta. 



Low, more or less tufted perennials; sepals purplish, rarely greenish. 



Herbage dark green, mostly glabrous; pods nearly straight; seaboard species 



4. A. blephurophylla. 

 Herbage more. or less canescent; pods arcuate; montane species 5. A. brezveri. 



1. A. virginica (L.) Trelease. Annual or biennial, nearly glabrous; 

 branched from the decumbent base, the branches 7 to 15 in. high; leaves, 

 deeply pinnatifid with nearly uniform oblong or linear few-toothed or entire 

 segments; flowers small, white, on very short pedicels; pods spreading, % to 1 

 in. long, 1 line broad, borne on pedicels 1 to 2 lines long, beaked by a short 

 pointed style; valves faintly veined or obscurely 1-nerved at base; seeds in 1 

 row. — (A. ludoviciana C. A. Mey.) 



Lower San Joaquin River banks, San ford; probably introduced from South- 

 ern California. 



2. A. glabra (L.) Bernh. Tower Mustard. Biennial; stems bluish 

 green, erect, simple (very rarely branched), 2 to 4 ft. high; herbage glaucous. 

 at the base hispidulous, above glabrous; radical leaves broadly spatulate, 

 coarsely dentate or merely denticulate, 2 to 4% in. long, soon withering; cauline 

 leaves ovate or ovate-lanceolate, entire, clasping by a sagittate base; flowers 

 dull white, 2 to 3 lines long, little exceeding the sepals; pods strictly erect, even 

 appressed to the stem, straight, 3 to 4 in. long, % to % line wide, on pedicels 

 3 to 5 lines long; seeds in 2 rows, narrowly winged or wingless. — (A. per- 

 forata Lam.) 



Throughout California: not rare, but the plants commonly solitary. Apr.- 

 May. 



3. A. hirsuta Scop. Hairy Rock Cress. Biennial, more or less hirsute, 

 deep green, not glaucous; stems erect, simple or strictly branched, 1 

 to 3 ft. high; radical leaves oblanceolate, the petioles winged, 1 to 2 in. 

 long; cauline oblong to lanceolate, commonly entire, sessile by a subcordate 

 base; petals dull white, 1% to 3 lines long; pods strictly erect on slender 

 pedicels, 1 to - in. long, V> line wide; style scarcely any; valves faintly 

 nerved below the middle and more or less veined; seeds suborbicular, very 

 narrow lv margined. 



Northern California; Marin Co. (ace. to Greene.) 



4. A. blepharophylla H. & A. Biennial or perennial, branched at base 

 OT simple, I to 1 2 in. high, deep green, glabrous, or somewhat hirsute below; 



leaves ciliate with forked hairs, the radical broadly spatulate to obovate, ob- 

 tuse, the cauline oblong, sessile, dentate or entile; (lowers large, fragrant, pur- 



