148 



CRUCIFERAE. 



Vol. II. 



Pods very broad and flat. 



l"'lowers yellow ; pods finely veined. j-. Sclenia. 



Flowers purple ; pods reticulate-veined. 38. Liiiiaria. 



B. Cotyledons conduplicate ; 

 TioN (Bkassiceae). 



Silique dehiscent. 



Beak of the silique stout, fiat or angled, 

 Valves 3-nerved. 

 Valves with i strong nerve. 

 Beak of the silique conic, often short. 



Silique terete ; seeds in i row in each cell. 41. Brassica. 



Silique flattened ; seeds in 2 rows in each cell. 42. Diplotaxis. 



Silique indehiscent. 43. Raf'hanus. 



2. Pod transversely 2- jointed; fleshy, seaside herbs (Cakileae). 44. Cakile. 



POD (.silique) elongated, beaked; weeds of cultiva- 



39. Sinapis. 



40. Eruca. 



I. DRABA [Dill.] L. Sp. PI. 642. 1753. 



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

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

 glabrous or pubescent. Stigma nearly entire. Seeds wingless, arranged in 2 rows in each 

 cell of the pod, numerous ; valves dehiscent, nerveless ; cotyledons accumbent. [Greek name 

 for some plant of this family.] 



Species about 175, mainly natives of the north temperate and arctic regions, a few in southern 

 South America. Besides the following, some 30 others are natives of western North America. Type 

 species : Draba vcrna L. 



Flowers white. 



Petals deeply 2-cleft. 



Petals entire, toothed, or emarginate. 



Flowering stems scapose, leafy only below. 

 Plants annual, not arctic. 



Leaves entire, obovate or oblong. 

 Leaves dentate, cuneate. 

 Low arctic perennials. 



Leaves stellate-canescent. 

 Leaves pilose-ciliate or glabrous. 

 Flowering stems leafy throughout up to the inflorescence. 

 Leaves remotely low-dentate or entire. 

 Basal leaves loosely pubescent, ciliate. 

 Basal leaves densely stellate-canescent. 

 Fruiting pedicels divergent. 

 Fruiting pedicels nearly erect. 

 Leaves sharply dentate. 

 Flowers yellow. 

 Stems leafy. 



Pods oblong, i"-2" long. 



Pods linear or lanceolate, 3"-6" long. 



Annual : pods 3"-4" long ; pedicels divaricately spreading. 

 Perennial ; pods 4"-/" long; pedicels erect. 

 Stems scapose. 



I. D. verna. 



2. D. caroliniana. 



3. D. cuneifolia, 



4. D. fladnisensis. 



5. D. nivalis. 



6. Z?. incana. 



7. D. arabisans. 



8. D. stylaris. 



9. D. ramosissima. 



10. D. brachycarpa, 



1 1. D. neniorosa. 



12. D. aurea, 



13. D. alpiim. 



I. Draba verna I.. A'ernal Whitlow-grass. Shad-llower. Nailwort. Fig. 1997. 



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



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



Annual or biennial, the leafless scapes numerous, I'-s' 

 high, erect or ascending, arising from a tuft of basal leaves, 

 which are oblong or spatulate-oblanceolate, i'-i' long, den- 

 tate or nearly entire, acutish and pubescent with stiff 

 stellate hairs: scapes nearly glabrous; flowers white, cleis- 

 togamous, iJ"-2" broad; petals deeply bifid; pedicels 

 ascending, i'-i' long in fruit; racemes elongating; pods 

 oblong to oval, glabrous, 3"-4" long, i" broad, obtuse, 

 shorter than their pedicels; style minute; seeds numerous. 



In fields, Massachusetts to New York, Minnesota. Georgia 

 and Tennessee. Recorded from Quebec. Naturalized from 

 Europe. Occurs also in Washington and British Columbia. 

 Native of Europe and western Asia. Consists of a great many 

 slightly differing races. White-blow. Feb.-May. 



