422 



CKUCII KKAK (MUSTARD FAMILY) 



Petals white. 



Valves of pod conspicuously keeled 

 Valves of pod rounded or flat. 

 Pods terete 

 Pods more or less flattened 



18. ALLIARIA. 



23. RADKTI.A. 

 30. CARDAMINK. 



h. Hairs at least in part branched. 



Stigma obtusely cone-shaped ; petals purple, 15-20 mm. long . . . 21. HKSPKKIS. 

 Stigma otherwise ; petals smaller. 

 Pods terete or 4-angled, sometimes torulose. 



Tall, 6-12 dm. high ; pods 8 cm. long ....... 31. ARAIH-. 



Not over 3 dm. high ; pods shorter. 

 Annual; pods not torulose ........ 19. SISYMHKIUM. 



Perennial ; pods more or less torulose ...... 20. BRAYA. 



Pods decidedly flattened. 



Pods lanceolate to narrowly oblong, rarely over 13mm. in length . 1. DRABA. 

 Pods linear, when normal and mature 15-80 mm. long . . .81. ARABIS. 



1. DRABA [Dill.] L. 



Pod oval, oblong, or even linear, flat ; the valves plane or slightly convex ; 

 the partition broad. Seeds several or numerous, in 2 rows in each cell, 

 marginless. Cotyledons accumbent. Filaments not toothed. 

 Low herbs with entire or toothed leaves, and white or yellow 

 flowers; pubescence often stellate. (Name from 8pd^, applied 

 by Dioscorides to some cress ; meaning unknown.) 



\NJfft 1. ER6PHILA (DC.) Reichenb. Annual or Mr nn 'ml ; flowers 

 \. J white, cleistogamous ; petals 2-cleft. 



V f , 1. D. VERNA L. (WHITLOW GRASS.) Small (scapes 2.5-8 cm. 

 high) ; leaves all radical, oblong or lanceolate ; racemes elongated in 

 781 D verna ^ ruit ' P oc * s varvin from round-oval to oblong-lanceolate, smooth, 

 Part of fruiting snorter tnan tne pedicels. Sandy waste places and roadsides, 

 raceme x a/ e - Mass. to Minn, and southw. A species remarkable as an 

 Petal x 1%. aggregate of many closely related forms which, from their cleis- 

 togamy, seldom cross or intergrade. Apr., May. (Nat. from 

 Eu.) FIG. 731. 



2. DRABELLA DC. Winter annuals ; leafy stems short; leaves oblong or 

 obovate, hairy, sessile; petals entire or merely emarginate, white (yellow in 

 no. 4) ; style none. 



2. D. caroliniana Walt. Small (2.5-12 cm. high) ; pedun- 

 cles scape-like ; petals usually twice the length of the calyx ; 

 raceme short or corymbose in fruit (1.2-2.5 cm. long); pods 

 broadly linear, smooth, much longer than the ascending pedi- 

 cels. Sandy and waste fields, e. Mass, to Minn., Neb., 

 and southw. March-May. FIG. 7:52. Petals often wanting 

 in the later racemes, especially in the var. MICRAXTHA (Nutt.) 



Gray, with minutely rough-hairy pods, 



which is found with the other, westw. 



3. D. cuneifblia Nutt, Leaves obovate, 

 wedge-shaped, or the lowest spatulate, 

 toothed ; raceme somewhat elong<it<'<! in. 

 fruit (2.5-7.5 cm.), at length equaling the 

 naked peduncle; petals emarginate, much 

 longer than the calyx ; />nds <>hlon<i-h'ni'in\ 

 inhinti'l)! liuiriji fniit/i rth<ni flu- spreading 

 pedicels. Grassy places, Ky., 111.? to e. 

 Kan., southw., and south westw. March, 

 Apr. FIG. 733. 



4. D. brachycdrpa Nutt. Low (5-10 

 cm. high), minutely pubescent; >/;/> 

 leaf;/ to the l>asc of the dense at length 



784. D. brachycarpa. elongated rarrme ; leaves (4-^8 mm. long) 788. D. cuneifolia. 

 Inflorescence x */ 8 . narrowly oblong or the lowest ovate, few- Fruiting raceme x Vs- 



732. D. caroliniana. 

 Fruiting raceme x 2 / 3 . 

 Fruit with valves re- 

 moved x 



