82 Flora of the Palouse Regio?i 



rather dense racemes: sepals oblong to linear, rather short: style 

 short; stigma entire: pods slender, terete or 4-angled; seeds oblong, 

 in one row in each cell. 



T. laciniatum Endl. Biennial, glabrous: stem stout, .5-1 m. tall, simple 

 or somewhat branched: leaves ovate or lanceolate, irregularly pinnatifid; 

 terminal lobe largest, coarsely dentate or entire; lateral lobes oblong or lin- 

 ear, entire or dentate, sometimes wanting: racemes dense, 5-40 cm. long: 

 sepals pale or purple: petals yellowish: pod slender, spreading, 5-12 cm. 

 long; pedicels stout, 5-8 mm. long. Crevices of basaltic cliffs along Snake 

 River. 



127. LEPIDIUM. 



Erect or diffnse annual or biennial herbs: leaves pinnatifid, 

 toothed or entire: flowers small, white or greenish, in racemes: 

 pod orbicular or obovate, much flattened at right angles to the 

 partition, 2-winged at the summit; seeds flattened, solitary in each 

 cell. 



Petals none. L. apetalum. 



Petals present. L. medium. 



L. apetalum Willd. Annual, erect, branched above, 30-90 cm. tall, min- 

 utely puberulent, at least below: lower leaves lanceolate, incisely serrate or 

 lobed, 3-5 cm. long and petioled; upper narrower, sometimes entire: racemes 

 elongate, densely flowered: petals none: pod orbicular, notched, glabrous, 

 3 mm. long, on longer pedicels. Plentiful in sandy soil. 



L. medium Greene. Much like the above but petals present, about as 

 long as the sepals: leaves nearly serrate, seldom lobed: stamens usually'6, 

 but sometimes only 2: pods glabrous or puberulent. Banks of Snake River. 



128. THIvASPI. 



Glabrous annual or perennial herbs: basal leaves entire or 

 toothed; cauline oblong, auricled and clasping: flowers white or 

 purplish: pod more or less compressed at right angles to the par- 

 tition, the valves often winged at the apex; seeds 2-4 in each cell. 



T. arvense h. Annual, erect, glabrous, simple or branched, 15-40 cm. 

 high: radical leaves oblanceolate, petioled; cauline oblong, obtuse, sagittate 

 and half-clasping: petals white, spatulate, exceeding the sepals: pod orbicu- 

 lar, 8-12 mm. long, broadly winged, deeply notched. A bad weed, very 

 sparingly introduced as yet. 



129. SISYMBRIUM. 



Mostly annual or biennial herbs: leaves neither clasping nor 

 auriculate at the base, rarely entire, often finely dissected: flowers 

 small, usually yellow or yellowish: style short or none: stigma 

 2-cleft: pod linear, short or long, flat or terete; seeds oblong, in one 

 row in each cell, 



