CRUCIFERAE. 119 



Radicula nasturtium-aquatica (L.) Britt. & Rendle. Perennial, aquatic, 

 smooth; stems procumbent, rooting at the lower nodes, 10-30 cm. high; 

 leaves pinnate; leaflets 3-11, orbicular or oblong, sinuate, or the lower ones 

 sometimes reduced to the terminal leaflet; petals white, 3-4 mm. long; pods 

 linear, 12-20 mm. long, acute at each end, a little longer than the spreading 

 pedicels. Introduced. Cultivated under the name of Water cress. 



Radicula sinuata (Nutt.) Greene. Stems prostrate or decumbent, branched, 

 glabrous or slightly scurfy-pubescent, from perennial creeping rootstocks; 

 leaves lanceolate or oblong, 2-3 cm. long, pinnatifid into numerous equal 

 linear or oblong lobes, these entire or nearly so; flowers 3-4 mm. long, yellow; 

 pod oblong, 6-8 mm. long, acute at each end, tipped with the long style; 

 pedicels spreading, 5-8 mm. long. Sandy banks of Snake River at Almota. 



Radicula pacifica (Howell) Greene. Annual or biennial, glabrous or nearly 

 so, erect, 30-90 cm. high; leaves lanceolate, pinnately cleft or parted, petioled, 

 5-15 cm. long, the segments toothed; pods oblong, turgid, 8-12 mm. long, 

 equalling the spreading pedicels. In wet places. 



Radicula curvisiliqua (Hook.) Greene. Annual or biennial, glabrous or 

 slightly pubescent, erect or decumbent, 15-40 cm. high; leaves oblanceolate, 

 sinuate-dentate or pinnately cleft into oblong dentate lobes; flowers small, 

 pale yellow; petals 2 mm. long, exceeding the sepals; pods linear-oblong, 4-16 

 mm. long; styles stout or none. Wet places, common and variable. 



Radicula obtusa (Nutt.) Greene. Annual or biennial, glabrous or nearly 

 so, branching from the base, spreading; leaves pinnately parted or divided, or 

 the upper often subentire and oblong; pedicels 2-4 mm. long, ascending or 

 spreading; flowers yellow; pods usually long, straight; style very short and 

 thick. Spokane County. 



164. 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. 



Pubescence of simple hairs or rarely wanting. 



Leaves pinnatifid into rather large irregular segments. S. officinale. 



Leaves pinnatifid in nearly equal linear segments. 5. altissimum. 



Pubescence of forked hairs or rarely wanting. 



Leaves tripinnate. S. sophia. 



Leaves pinnatifid or bipinnatifid. 



Green; seeds in 1 row. 5. incisum. 



Canescent ; seeds in 2 rows. S. canescens. 



Sisymbrium officinale leiocarpum DC. Hedge Mustard. Erect, sparsely 

 hirsute with simple hairs, or glabrous, 30-90 cm. high, divaricately branched 

 above; leaves pinnatifid into 5-13 lobes, the terminal longest, all more or less 

 dentate; upper cauline leaves sessile, the others petioled; flowers yellow, 3 mm. 

 broad; pods glabrous, tapering from the base to the apex, 1-2 cm. long, erect, 

 on short pedicels. A weed in waste ground. 



Sisymbrium altissimum L. Tumbling Mustard. Erect, much branched, 

 60-150 cm. tall, glabrous or sparsely hirsute, with simple hairs; basal leaves 

 petioled, pinnatifid, in linear or lanceolate entire or dentate lobes; upper 

 leaves reduced, sessile; flowers pale yellow, 5 mm. broad; pods spreading, 

 linear, 6-10 cm. long, on short stout pedicels. A troublesome weed, introduce 

 from Europe. Locally called Jim Hill Mustard. 



