MUSTARD FAMILY. 189 



and falling in a close coil while still green-herbaceous; pedicels 2 lines long, 

 little accrescent in fruit. 



Under oaks and other trees in openly wooded country. Oakland Hills and 

 M;u in Co. to Napa Valley and Mendocino Co. and far northward. 



13. TROPIDOCARPUM Hook. 

 Erect or diffusely spreading annuals with pubescent herbage, pinnatifid 

 leaves and leafy racemes of rather small yellow flowers. Sepals concave, ovate- 

 oblong, spreading. Petals cuneate-obovate. Stamens tetradynamous ; anthers 

 roundish. Style slender, sometimes short. Pod completely or partially 2-celled, 

 or 1-celled, strongly flattened contrary to the narrow partition, or only the 

 upper part flattened, or somewhat inflated; valves 2 to 4, opening from above; 

 seeds in 2 to 4 rows. (Greek tropis, keel, and karpos, fruit, in reference to 

 the carinate valves of the capsule. For an interesting study of the fruit of 

 Tropidocarpum see Robinson in Erythea, iv. 109.) 



Plants, when robust, with mostly straggling branches; pods 2-valved and 



Two-celled 1. T. gracile. 



One-celled, but the partition persistent above 2. T. dubium. 



Plants commonly erect; pods 4-valved and 1- celled 3. T. capparideum. 



1. T. gracile Hook. Erect or at last very diffuse; leaves pinnatifid, 

 the segments commonly linear, acutish, cleft or entire; leaves of the inflores- 

 cence similar but reduced; pedicels axillary, 3 to 10 lines long, spreading; 

 stamens very unequal; pods linear, strongly obcompressed throughout, tardily 

 dehiscent; style slender; seeds in 2 rows. 



On or near low hills of the inner Coast Ranges from Tehama Co. and the 

 Marysville Buttes southwestward to Vacaville, Mt. Diablo and Southern Cali- 

 fornia. Although a native it finds improved conditions of existence in the 

 lower San Joaquin Valley, an agricultural region (E. W. Hilgard, 1890). 



2. T. dubium Davidson. Decumbent, the branches 6 to 12 in. long; 

 radical leaves regularly pinnatifid with 3-toothed segments, petioled, 2 to 3 in. 

 long; cauline leaves mostly sessile, with linear segments; stamens tetradynamous, 

 but not markedly unequal; pedicels said to be arcuate; pods y* to 1% in. 

 long, 1 line wide, only the upper portion obcompressed; partition not present, 

 except in the upper third or fourth. 



Eastern Contra Costa Co. and Southern California. 



3. T. capparideum Greene. Stem stoutish, erect, mostly less than 1 

 ft. high, simple or sparingly branched; foliage as in T. gracile, the upper 

 leaves somewhat more deeply parted and with longer subentire segments; pods 

 linear-oblong, 7 to 10 lines in length, 2 lines wide, somewhat inflated, 1-celled, 

 conspicuously 6-nerved, tipped with a slender style; valves 4, the dehiscence 

 beginning at the apex; seeds in 4 distinct rows. 



Alkaline soil from Byron to Lathrop. 



14. CAPSELLA Medic. 



Slender annuals with pinnatifid leaves and small white flowers. Petals 



small, little exceeding the sepals. Pod obcordate or elliptical, strongly or 



scarcely at all flattened, several-seeded; valves carinate. Seeds not winged; 



cotyledons incumbent. (Latin capsella, a little box, in allusion to the fruit.) 



Pod obcordate, or cuneate-triangular in outline with retuse apex, strongly flattened 



1. C. bursa-pastoris. 

 Pod elliptic-oblong, scarcely flattened, entire at the apex 2. C. procumbens. 



1. C. bursa-pastoris Moench. Shepherd's Purse. Stems erect, simple 

 or branching, 3 to 10 or 15 in. high, sparsely hispid; radical leaves in a 



