460 FLORA. 



Rapfstrum rugbsum (L.) All., a plant with 2-jointed indehiscent pods, erect on 

 appressed pedicels, in long racemes, has been found as a waif at Easton, Penn., and 

 plentifully in ballast about the seaports. It is nearly related to Raphanus. 



30 DRABA L. 



Low tufted mostly stellate-pubescent herbs, with simple leaves, and mainly 

 racemose flowers. Silicles elliptic, oblong or linear, flat, few to many-seeded. 

 Stigma nearly entire. Seeds wingless, in 2 rows in each cell of the pod, numer- 

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

 plant of this family.] Species about 150, mainly natives of temperate and arctic 

 regions. Besides the following, some 25 others occur in western N. Am. 



Flowers white or whitish. 



Petals deeply 2-cleft. I. D. verna. 



Petals entire, toothed, or emarginate. 



Flowering stems scapose, leafy only below. 

 Plants annual, not arctic. 



Leaves entire, obovate or oblong. 2. D. Caroliniana. 



Leaves dentate, cuneate to spatulate. 3. D. cuneifolia, 



Low arctic perennials. 



Leaves pilose-ciliate or glabrous. 4. D. Fladnizensis. 



Leaves stellate-canescent. 5. D. nivalis. 



Flowering stems leafy throughout up to the inflorescence. 



Leaves entire or sparingly dentate. 6. D. incana. 



Leaves sharply dentate. 7. D. ramosissima. 



Flowers yellow ; stems leafy. 



Pods oblong, 2-4 mm. long. 8. D. brachycarpa. 



Pods linear or lanceolate, 6-14 mm. long. 



Annual ; pods 6-8 mm. long ; pedicels divaricately spreading. 



9. D. ncmorosa. 



Perennial ; pods 8-14 mm. long ; pedicels erect. 10. D. aurea. 



Flowers yellow ; stems scapose. n. D. alpina. 



1. Draba verna L. VERNAL WHITLOW-GRASS. (I. F. f. 1755.) Annual, 

 the leafless scapes numerous, 2-13 cm. high, arising from a tuft of basal leaves, 

 which are oblong or spatulate-oblanceolate, 1-2.5 cm. long, acutish and pubescent 

 with stellate hairs; flowers 3-4 mm. broad; pedicels 1-2.5 cm. long in fruit; pods 

 oblong, glabrous, 68 mm. long, 2 mm. broad, obtuse, shorter than their pedicels; 

 style minute; seeds numerous. In fields, common except in the extreme north. 

 Nat. from Europe. Feb.-May. 



2. Draba Caroliniana Walt. CAROLINA WHITLOW-GRASS. (I. F. f. 1756.) 

 Annual; scapes 2-13 cm. high from a short leafy stem. Leaves tufted, obovate, 

 8-20 mm. long, obtuse, entire or rarely with 3 or 4 teeth, pubescent with stellate 

 hairs; scapes nearly glabrous ; flowers 3-4 mm. broad ; petals entire, sometime? 

 wanting in the later flowers; pedicels 2-4 mm. long in fruit; pods linear, 8-12 mm. 

 long, nearly 2 mm. broad, glabrous ; style none. In sandy fields, Mass, to Ont. , 

 Minn., Neb., Ga. and Ark. March-June. 



Draba Carolini&na micrdntha (Nutt.) A. Gray. Differs from the type in the ap- 

 pressed-hispid pods. Petals often wanting. Prairies, 111. to Tex., N. Mex. and Wash. 



3. Draba cuneifolia Nutt. WEDGE LEAVED WHITLOW-GRASS. (I. F. f. 1757.) 

 Annual, stellate -pubescent, 1-2 dm. high, branching and leafy below. Leaves 

 obovate, cuneate, or the lowest spatulate, 1-4 cm. long, obtuse, dentate toward the 

 apex ; flowers 4 mm. broad ; petals emarginate, twice or thrice the length of the 

 calyx; pedicels ascending or spreading, 4-8 mm. long in fruit; pods linear-oblong, 

 obtuse, 8-10 mm. long, 2 mm. wide, minutely hairy; style none. In fields, Ky. 

 to Kans., Fla. and Cal. Feb.-April. 



t. Draba Fladnizensis Wulf. WHITE ARCTIC WHITLOW-GRASS. (I. F. f. 

 . .) Tufted. Leaves oblanceolate, basal, rosulate, acutish, entire, stellate- 

 canescent or with some simple hairs, ciliate or rarely nearly glabrous, 8-16 mm. 

 long; flowers whitish; scapes glabrous; pedicels ascending, 2-4 mm. long in fruit; 

 pods oblong, glabrous, 4-6 mm. long, nearly 2 mm. wide; style almost wanting. 

 Gaspe, Quebec, and through arctic America, south in the Rocky Mts. to Colo. 

 Also in arctic and alpine Europe and Asia. Summer. 



