thlaspi. CRUCIFERvE. 65 



HETERODJRABA. 



T. alpestre L. Sp. ed. 2, ii. 903 (?) Stems simple, or branched from 

 the base, from a quite simp'e or branched perennial rootstock, 1-15 inches 

 high: radical leaves rosulate, elliptical to spatulate, attenuate to a slender pet- 

 iole, 6-12 lines long or more, entire or sparingly toothed ; cauline ovate to ob- 

 long, entire, acuminate, clasping at base, 3-6 lines long: flowers 2-3 lines 

 long, croAvded in a somewhat capitate cluster; sepals purplish, thin-mar- 

 gined; petals white, or pale purple, 3-4 lines long: peduncle at length elon- 

 gated: pedicels spreading, in fruit, 2-4 lines long : pods obovate to cuneate- 

 oblong, 3-4 lines long, emarginate or truncate or rounded at the apex 4-8- 

 seeded; style a line long. In mountainous districts, California to Brit. Col- 

 umbia and the Rocky Mountains. 



Tribe VIII. Isatedese DC. Pods short, rarely elongated, inde- 

 hiscent, inarticulate, usually crustaceous or osseous, 1-celled, 1- 

 rarely 2-seeded. Pedicels usually slender, recurved in fruit. Coty- 

 ledons accumbent . 



33 HETERODRABA Greene, Bull. Gal. Acad. i. 71. 



Slender annual with long horizontal and nearly prostrate 

 branches. Sepals equal at base. Petals minute or wanting. Stig- 

 ma sessile. Pod short-elliptical, twisted, very tardily if at all 

 dehiscent, by a very filmy partition 2-celled : valves flat, nerve- 

 less. Seeds 3-5 in each cell, in two rows. Cotyledons accumbent. 



H. unilateralis Greene 1. c. 27 Draba unilateralis M. E. Jones Bull. Torr. 

 Club, ix, 124. Hirsute-pubescent with branching hairs: leaves obovate, 

 with cuneate base, 6-12 lines long, sparingly toothed towards the apex, 

 branches from a, few inches to more than a foot long, spreading horizontally : 

 flowering and fruiting throughout their whole length : pods 2 lines long, 1% 

 lines wdde, with some stout straight hairs besides the stellate pubescence 

 in maturity twisted : pedicels scarcely a line long, stout and deflexed. In 

 open moist places, southern Oregon, near Ashland and California. 



34 ATHYSANUS Greene, 1. c, 72. 



Slender annual with rosulate usually toothed leaves and 

 small white flowers in long racemes. Sepals equal at base. 

 Petals small or none. Style very short. Pods orbicular, not 

 margined, indehiscent, flat, nerveless, 1-celled, 1-seeded. Cotyl- 

 dons accumbent. 



A. pusillus Greene 1. c. Thysanocarpus pusillus Hook. Inc. t. 42. Hir- 

 sute-tomentose with stellate hairs; stems very slender, branching from near 

 the base, the filiform branches 3-12 inches long: lower leaves broadly oblan- 

 ceolate, entire or remotely denticulate, 3-12 lines long, short-petioled ; cau- 

 line similar, but smaller, often entire, sessile but not clasping: flowers bare- 

 ly a line broad, the late ones apetalous: pods orbicular, less than a line 

 broad, hirsute with hooked hairs, ; pedicels 1-2 lines long, at length reflex- 

 ed. Common on dry hillsides and rocky banks, southern California to 

 Brit. Columbia: flowering in very early spring. 



35 THYSANOCARPUS Hook. Fl. i, 69, t. 18. f. A. 



Slender erect sparingly branched annuals with minute white 

 or rose-color flowers on slender pedicels in elongated racemes. 

 Sepals equal at base. Petals minute. Stamens 6, subequal, 

 free, unappendaged, with slender filaments and short anthers. 

 Pods orbicular, wing-margined, much compressed, plano-convex, 



