422 



CRUCIFEKAE (MUSTARD FAMILY) 



Petals white. 



Valves of pod conspicuously keeled 18. ALLIABIA. 



Valves of pod rounded or flat. 



Pods terete 23. EADICULA. 



Pods more or less flattened 30. CAP.DAMINB. 



h. Hairs at least in part branched. 



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

 Stigma otherwise ; petals smaller. 

 Pods terete or 4-angled, sometimes torulose. 



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



Not over 3 dm. high ; pods shorter. 



Annual ; pods not torulose . . 19. SISYMKP.ICM. 



Perennial ; pods more or less torulose 20. BRATA. 



Pods decidedly flattened. 



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

 Pods linear, when normal and mature 15-SO mm. long . . .31. 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 dpdpr), applied 

 by Dioscorides to some cress ; meaning unknown.) 



1. ER6PHILA (DC.) Reichenb. Annual or biennial ; flowers 

 lohite, cleistogamous ; petals 2-cleft. 



1. D. viiRNA L. (WHITLOW GRASS.) Small (scapes 2.5-8 cm. 

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

 781 D verna ^ ru ^ '> Pds varying from round-oval to oblong-lanceolate, smooth, 

 Part of fruiting shorter than the pedicels. Sandy waste places and roadsides, 

 raceme xz/ e - M ass - 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. 732. Petals often wanting 

 in the later racemes, especially in the var. MICRANTHA (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 elongated in 

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

 naked peduncle; petals emarginate, much 

 longer than the calyx ; pods oblong-linear, 

 minutely hairy, longer than the spreading 

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

 Kan., southw., and southwestw. March, 

 Apr. FIG. 733. 



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

 cm. high), minutely pubescent ; stems 

 leafy to the base of the dense at length 



784. D. brachycarpa. elongated raceme ; leaves (4-8 mm. long) 738. D. cuneifolia. 



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



732. D. caroliniana. 

 Fruitinp raceme x 2 / s . 

 Fruit with valves re- 

 moved x 



