CRUCIFERAE. 181 



purplish; pod more or less compressed at right angles to the 

 partition, the valves often winged at the apex; seeds 2-4 in 

 each cell. 



Pods large, winged, deeply notched; annual. T. arvense. 



Pods small, scarcely winged or notched; perennial. T. alpestre. 



Thlaspi arvense L. Penny Cress. 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 orbicular, 8-12 mm. long, broadly winged, deeply notched. 



A weed, sparingly introduced. 



Thlaspi alpestre L. Perennial, glabrous and green; stems usually several 

 from a branched base, 10-20 cm. high; basal leaves obovate or elliptic, petioled, 

 entire or toothed; cauline oblong, entire, sessile and somewhat auriculate; 

 flowers white; pods obovate, emarginate at apex, 4-8 mm. long. 



At high altitudes in the Cascade Mountains. 



238. BURSA. 



Slender and mostly smooth annual herbs; radical leaves tufted; 

 flowers small, w r hite, in racemes; pods cuneate, notched at apex, 

 compressed at right angles to the partition, many-seeded. 



Bursa bursa-pastoris (L.) Weber. Shepherd's Purse. Stellate-pubescent 

 below, glabrous above, 30-60 cm. tall, sparingly branched; basal leaves in a 

 rosette, lanceolate or oblanceolate, pinnately-lobed, 2-8 cm. long, dentate or 

 entire; flowers white, about 2 mm. long; pods triangular, cuneate, with a 

 broad shallow notch at the apex. 



A common weed. 



239. HUTCHINSIA. 



Low spreading annual with entire or pinnately-lobed leaves; 

 flowers minute, white, in crowded racemes which elongate in fruit; 

 stigma sessile or nearly so; silicle oval, compressed at right angles 

 to the partition, not cuneate, not notched at the apex; each 

 valve conspicuously 1 -nerved. 



Hutchinsia procumbens (L.) DC. Branched from the base, glabrous or 

 sparsely pubescent, 5-15 cm. high; stems decumbent or ascending; basal 

 leaves pinnately lobed or entire; petioles 12 cm. long; cauline leaves spatulate 

 or oblanceolate, sessile, entire or with a few lobes; petals white, about as 

 long as the sepals, 1 mm. long; pods smooth, elliptic, 3-4 mm. long, on slender 

 pedicels. 



In moist ground, rare in our limits. 



240. CAMELINA. FALSE FLAX. 



Erect annual herbs; leaves entire, toothed or pinnatifid; 

 flowers small, yellowish; style slender; pod obovoid or pear- 

 shaped, slightly flattened parallel to the partition, many-seeded. 



Pods 4-5 mm. long; herbage pubescent toward the base. C. microcarpa. 



Pods 6-8 mm. long; herbage glabrous or nearly so. C. saliva. 



