292 



BRASSICACEAE 



40. DRABA [Dill.] L. Sp. PL 642. 1753. 



Low tufted mostly stellate-pubescent herbs, with scapose or leafy stems, simple leaves, 

 and racemose flowers. Silicles elliptical, oblong or rarely linear, flat, few- to many-seeded. 

 Stigma nearly entire. Seeds numerous, arranged in 2 rows in each cell, winged or wing- 

 less ; valves dehiscent, nerveless ; cotyledons accumbent. [Greek name for some member 

 of the family.] 



About 175 species, mainly of the north temperate and arctic regions, a few in southern South America. 

 Type species, Draba verna L. 



1. D. verna. 



2. D. reptans. 



D. platycarpa. 

 D. sonorae. 



5. D. brachycarpa. 



6. D. nemorosa. 



7. D. stenoloba. 



8. D. lonchocarpa. 



Annuals. 



Petals bifid. 



Petals entire or merely emarginate. 



Flowers white, dimorphous, the smaller ones cleistogamous. 

 Fruiting racemes short and compact; leaves basal. 

 Fruiting racemes elongated and open. 



Pods ellipsoid, rounded at apex, coarsely pubescent with upwardly appressed and^ rather stiff 



simple hairs. 

 Pods oblong, obtuse at the apex, stellate-pubescent or glabrous. 

 Flowers yellow, not dimorphous. 



Pods 2-4 mm. long, the pedicels scarcely as long; petals sometimes wanting. 

 Pods 5-15 mm. long; petals always present. 



Pods 5-8 mm. long; pedicels usually much longer. 

 Pods 10-15 mm. long; pedicels usually shorter. 



Perennials. 



Flowering stems scapose. 



Style none; pods linear, 10-15 mm. long. 

 Style evident, 0.5-3 mm. long. 



Pods strongly flattened; style stout, 0.5-1 mm. long. 



Leaves oblanceolate or obovate, not firm and midvein not prominent. 



Leaves densely stellate-pubescent, without cilia, obovate; seeds not winged. 



Pedicels very short, scarcely evident in anthesis. 9. D. ruaxes. 



Pedicels slender, mostly 4-6 mm. long in anthesis. 10. D. Cusickii. 



Leaves ciliate on the margins, rather obscurely so in incerta, oblanceolate. 

 Leaves loosely stellate, the margins weakly ciliate toward the base. 



Seeds broadly winged all around or only at apex. 11. D. Howellii. 



Seeds not winged. 12. D. incerta. 



Leaves strongly ciliate on the margins, otherwise glabrous or with a few simple 

 hairs. 13. D. Lemmonn. 



Leaves linear or linear-oblong, firm, midvein prominent, conspicuously ciliate. 

 Leaves over 5 mm. long, not incurved; scapes usually over 3 cm. long. 



Leaves loosely stellate-pubescent, ciliate to the apex. 14. D. Paysonii. 



Leaves strongly ciliate on the margins, otherwise glabrous or with a few stellate 

 hairs toward the apex. 15. D. Nelsonn. 



Leaves not over 5 mm. long, closely imbricated and often incurved at apex. 

 Leaves glabrous except for prominent marginal cilia. 

 Leaves pubescent. 



Pubescence of short appressed stellate hairs. 

 Pubescence short-villous with forked and simple hairs. 

 Pods subovoid; style very slender, 1.5-2.5 mm. long; flowers white. 

 Flowering stems leafy. 

 Styles not evident. 

 Styles 1-3 mm. long. 



Style stout, 1-3 mm. long; pods usually obtuse at the apex. 

 Style almost filiform, 2-3 mm. long; pod very acute at apex. 



19. D. Douglasii. 



20. D. Breweri. 



21. D. 



22. D. 



aureola, 

 corrugata. 



1. Draba verna L. Vernal Whitlow-grass. Fig. 2065. 



Draba verna L. Sp. PI. 642. 1753. 

 Erophila vulgaris DC. Syst. 2: 356. 1821. 



Annual or biennial, with tufted basal leaves and several to many ascending or erect leafless 

 and nearly glabrous scapes, 5-15 cm. high. Leaves 15-25 mm. long, oblong or spatulate-oblanceo- 

 late, denticulate or nearly entire, pubescent with stiff stellate hairs; petals white, 3-4 mm. long, 

 deeply bifid; pods oblong or oval, 6-8 mm. long, glabrous; pedicels ascending, 15-25 mm. long 

 in fruit. 



A variable species, naturalized from Europe, occurring in the eastern United States and on the Pacific 

 Slope from British Columbia to northern California. Feb.-May. 



2. Draba reptans (Lam.) Fernald. Carolina Whitlow-grass. Fig. 2066. 



Arabis reptans Lam. Encyl. 1: 222. 1783. 

 Draba caroliniana Walt. Fl. Car. 174. 1788. 

 Draba reptans Fernald, Rhodora 36: 368. 1934. 



Annual, the stems branched from the base, 5-10 cm. high, more or less pubescent. Leaves 

 5-15 mm. long, ovate to elliptical, entire, stellate-pubescent; petals emarginate, usually shorter 

 than the sepals, sometimes wanting in older racemes ; fruiting racemes congested at the ends of 



