BRASSICACEAE 479 



19. DRABA L. 



Low annual or perennial scapose or caulescent herbs, often clothed with stellate pubes- 

 cence. Leaves alternate or basal : blades entire or toothed. Flowers perfect, in racemes. 

 Sepals 4, equal. Corolla white or yellow, sometimes pink or purple : petals 4, longer 

 than the sepals. Stamens 6. Ovary sessile : style short or elongated : stigma capitate. 

 Ovules 2-several in each cavity. Silicles elliptic to linear, flat : valves nerveless. Seeds 

 in 1 row in each cavity. Cotyledons usually accumbent. Whitlow Grass. 



Annuals or often winter-annuals : pods not spirally twisted : petals about twice as long as the sepals. 

 Petals 2-cleft. 1. D. vcrna. 



Petals entire, erose or emarginate. 

 Leaf-blades entire. 



Pods glabrous. 2. I>. Caroliniana. 



Pods pubescent. 3. I), micrantha. 



Leaf-blades toothed. 



Pods 5-15 mm. lo:ig : sepals 2 mm. long. 



Pods linear, oblong-linear or narrowly oblong. 



Racemes elongated : pods over 7 mm. long. 4. D. cuneifolia. 



Racemes umbel-like or corymbose : pods less than 7 mm. long. 5. B. HeUeri. 



Pods elliptic. " 6. D. platycarpa. 



Pods 2-3 mm. long: sepals barely 1 mm. long. 7. D. brachijcarpa. 



Perennial : pods spirally twisted : petals thrice as long as the sepals. 8. D. ramosissmta, 



1. Draba v^rna L. Annual, acaulescent, bright green. Leaves basal ; blades spat- 

 ulate, oblanceolate or narrowly oblong, 5-15 mm. long, obtuse or acute, entire or with sev- 

 eral teeth near the apex, pubescent with stellate hairs : scapes erect or ascending, usually 

 branched at the base, glabrous : pedicels liliform, a.scending, 0.5-2 cm. long : sepals oblong 

 or oval, 1 mm. long, obtuse': petals white, cuneate, 2-cleft, twice as long as the sepals : pods 

 elliptic or oblong-elliptic, or sometimes oval, 5-9 mm. long. 



In fields and waste places, widely distributed in southern British America and the United States. 

 Winter and spring. 



2. Draba Caroliniana Walt. Annual, more or less hispid, especially below. Leaves 

 approximate; blades oblong, obovate, sjjatulate or suborbicular, 0.5-1.5 cm. long, obtuse, 

 entire, or with several shallow teeth : scapes erect or ascending, often glabrous above, 2-10 

 cm. long: pedicels ascending or spreading, 1-8 mm. long: sepals oblong, 2-2.5 mm. long, 

 obtuse : petals wliite, spatulate-obovate, rounded or emarginate at the apex, about twice as 

 long as the sepals : pods linear, 7-18 mm. long, glabrous. 



In sandy soil and on rocks, Massachusetts to Minnesota,- Georgia and Arkansas, Spring. 



3. Draba micrdntha Nutt. Similar to D. Caroliniana in habit, but commonly more 

 branched at the base. Leaves mostly at the base of the i^lant ; blades spatulate to cuneate 

 or oblong, entire : scapes erect or spreading, longer than the stems : racemes abbreviated : 

 pedicels 2-4 mm. long : sepals ovate or oblong-ovate : petals white, about as large as those 

 of D. Caroliniana, or those of the later flowers much smaller or obsolete : pods linear, 12-18 

 mm. long, often slightly curved, pubescent. 



In sandy soil, Illinois to Washington, Texas and California. Spring. 



4. Draba cuneifolia Nutt. Annual, pubescent with stellate hairs. Stems 1-10 cm. 

 long, simple or branched : leaves approximate ; blades cuneate, obovate or the lower some- 

 times spatulate, 1-3 cm. long, obtuse or acutish, entire or coarsely toothed above : pedun- 

 cles erect or spreading, 3-20 cm. long : pedicels finally 2-7 mm. long, spreading or some- 

 what ascending : sepals oblong, 2 mm. long, obtuse': petals white, broadly spatulate, with a 

 broad sinus at the apex : pods linear-oblong, 8-15 mm. long, minutely pubescent with 

 simple hairs. 



In fields and on cliffs, Illinois to California, Florida and Texas. Spring. 



5. Draba H61Ieri Small. Annual, dwarf, scabrous-pubescent or merely puberulent 

 above. Leaves mainly basal, rather crowded ; blades spatulate to oblong, 4-11 mm. long, 

 slightly toothed, acute or acutish : scapes spreading or ascending, 1-4 cm. long, usually 

 4-8 togetlier, rougli puberulent to the top : racemes abbreviated or congested : pedicels as- 

 cending or spreading, 1-3 mm. long, puberulent like the scape : sepals oblong or ovate- 

 oblong, about 1 mm. long : petals white : pods narrowly oblong, 2-6 mm. long, minutely 

 pubescent. 



In dry or sandy soil, near Corpus Christi, Texas. Spring. 



6. Draba platycdrpa T. & G. Annual, finely pubescent all over. Leaves on the 

 lower part of the plant, but not crowded ; blades 1-2 cm. long, those of the basal and lower 

 cauline leaves cuneate to oblong, those of the upper cauluie oblong-lanceolate to lanceolate, 

 acute or acutish, all more or less serrate, usually rather coarsely so : scapes slender, longer 



