212 CRUCIFERAE (MUSTARD FAMILY) 



what truncately obtuse. " In great abundance at the head of the Yellowstone 

 Lake," Parry; infrequent but very widely distributed. 



7. LEPIDIUM L. PEPPERGRASS 



Annual, biennial, or perennial herbs, with entire, toothed, or pinnatifid 

 leaves tapering at base, and with small white or greenish flowers (which are 

 sometimes apetalous) in dense racemes. Stamens often fewer than 6. Silique 

 strongly flattened at right angles to the septum, oblong to orbicular, fre- 

 quently wing-margined especially toward the summit which thus becomes 

 more or less notched. Seeds flattened, solitary in each of the flattened keeled 

 valves. Cotyledons (in ours) incumbent. 



Style short but evident; biennials or perennials. 



Silique not notched at apex 1. L. Draba. 



Silique with shallow notch and short style. 



Leaves entire or merely toothed at apex .... 2. L. spatulatum. 



Leaves, in part at least, pinnately toothed, pinnatifid, or parted. 

 Linear-entire and linear-parted; perennials. 



Silique rhombic-ovate 



Silique orbicular 



Pinnatifid, or the upper entire; biennials. r 

 Branched from the crown of the thick root 

 Branched above, the base usually simple 



3. L. alyssoides. 



4. L. Fremontii. 



5. L. montanum. 



6. L. Jonesii. 



Style wanting; the stigma sessile in the notch of the silique. 

 Siliques glabrous. 



Petals wanting; root leaves incisely toothed or pinnatifid. 



Stem simple at base ........_ . . . 7. L. apetalum. 



Stem divergently branched from the base 

 Petals evident; root leaves entire or merely toothed 



Biennials. 



Stems several from the crown, widely spreading . . 10. L. ramosissimum. 



Stems single from the crown, branching from the base up 11. L. ramosum. 



Siliques pubescent. 



Stem hirsute with white hairs 

 Stem finely puberiilent . 



8. L. divergens. 

 L. medium. 



12. L. lasiocarpum. 



13. L. pubecarpum. 



1. Lepidium Draba L. Sp. PI. 645. 1753. Pubescent perennial, 2-4 dm. 

 high: leaves elliptic to elliptic-lanceolate, obtuse, denticulate, clasping by a 

 somewhat narrowed auricled base, 3-6 cm. long: petals white, conspicuous: 

 silique broadly ovate, subcordate at base, acutish at apex and tipped with 

 the short slender style. Adventive; infrequent; waste grounds. 



2. Lepidium spatulatum Vasey, Robins. Syn. Fl. 1: 125. 1895. Glabrous 

 perennial, 2-5 dm. high: stems usually several from the woody caudex, each 

 simple below, paniculately branching upward: leaves green, rather thick; 

 the lower oblanceolate, tapering gradually to the slender petiole, 3-toothed at 

 the apex, as are also some of the oblong shorter stem leaves : racemes numerous, 

 dense: petals white, exceeding the sepals: silique glabrous, ovate, minutely 

 notched at apex; style short. (L. crenatum Rydb.; Thely podium crenatum 

 Greene.) Western Colorado and in Utah. 



3. Lepidium alyssoides Gray, PL Fendl. 10. 1848. Probably perennial, 

 usually a few stems from the base which are corymbosely branched above, 

 glabrous or puberulent, about 2 dm. high: leaves glabrous, linear, 4-8 cm. 

 long; the lower pinnate with 2-3 pairs of linear lobes: racemes dense: petals 

 white, conspicuous: silique rhombic-ovate, the shallow notch occupied by 

 the short style. (L. Eastwoodiae Wooton, Bull. Torr. Bot. Club 25: 258. 

 1898, as to Colorado specimens; L. Crandallii Rydb. Bull. Torr. Bot. Club 

 34: 427. 1897.) Arid places; western Colorado, Utah, and southward. 



4. Lepidium Fremontii Wats. Bot. King's Rep. 5: 30. 1871. Glabrous and 

 glaucous: stems several from the woody caudex, paniculately branched above, 

 3-^4 dm. high: leaves linear, acute, 4-8 cm. long; some of the lower pinnate 

 with 1-3 pairs of linear teeth or lobes: flowers white: silique large, suborbic- 

 ular, very thin, acutish at base, cordately notched above; style very short. 

 Arid areas; Colorado and New Mexico to California. 



5. Lepidium montanum Nutt. T. & G. Fl. 1: 116. 183&. Nearly glabrous: 



