486 Cruciferae 



Seeds narrowly winged; stems pubescent; pods spreading or 

 erect, 2-4 cm long in nos. 2 and 3 of. .3001. Arabis, p. 504. 

 Seeds wingless. 



Stem leaves generally not more than 5 mm wide, entire or 

 nearly so; basal rosette of leaves pubescent but often 

 absent at fruiting time. 

 Petals 2-2.5 mm long; seed about 0.5 mm long in no. 3 of 



2917. Sisymbrium, p. 489. 



Petals mostly 3-5 mm long; seed about 1 mm long. no. 8 of 



3001. Arabis, p. 504. 



Stem leaves more than 5 mm wide, usually more or less 

 dentate. 

 Plants tall, glabrous, with leaves sagittate at the base; pods 



erect, 4-6 cm long in no. 6 of 3001. Arabis, p. 504. 



Plants not as above. 



Plants glabrous or more or less pubescent with simple 



hairs 2966. Cardamine, p. 497. 



Plants pubescent; hairs not simple in no. 4 of 



3001. Arabis, p. 504. 



A. Flowers yellow or creamy yellow. 



C. Pods not more than 3 times as long as wide. 



Pubescence stellate or forked; leaves entire or obscurely toothed. 

 Pods globose. 



Pods indehiscent, 2.5 mm in diameter, surface conspicuously reticulate, gen- 

 erally 1-seeded 2988. Neslia, p. 502. 



Pods dehiscent, 2 mm in diameter, smooth, about 4-seeded 



2983. Lesquerella, p. 502. 



Pods thin, flat, orbicular, with a winged margin, 3-4 mm long, few-seeded. 



3006. Alyssum, p. 509. 



Pubescence simple or lacking; leaves pinnatifid or toothed. . .2965. Rorippa, p. 494. 

 C. Pods 4-many times as long as wide. 



Pods indehiscent, moniliform, 2-3 cm long, much constricted between the seed when 



mature, up to 10-seeded, walls fleshy 2950. Raphanus, p. 492. 



Pods dehiscent, longitudinally 2-celled. 

 Seed in 2 rows in each cell. 



Pods nearly beakless 2997. Descurainia, p. 504. 



Pods with beaks about 2 mm long 2946. Diplotaxis, p. 490. 



Seed in 1 row in each cell. 



Racemes leafy-bracted ; leaves pinnatifid, with obtuse lobes 



2947. Erucastrum, p. 490. 



Racemes bractless. 



1). Leaves (at least the lower stem leaves) pinnate, bipinnate, more or less 

 pinnatifid or lobed. 

 Leaves oblong in outline, bipinnatifid, segments numerous, small, toothed 

 or obtuse; pedicels mostly 1-1.5 cm long. . .2997. Descurainia, p. 50 1. 

 Leaves not as above; seed in 1 row in each cell. 



Pods flat, generally 6-15 mm long, about 1 mm wide; creeping perennials, 

 often rooting at the lower nodes; flowers 3-4 mm long in no. 1 of . . . . 



2965. Rorippa, p. 41)4. 



Pods terete or 4-sided; annuals or perennials but not creeping. 



Plants tall, widely spreading; leaves large, deeply pinnatifid, the seg- 

 ments very long and narrow, those of the upper leaves 1.4 mm 

 wide and 2-5 cm long, or filiform; flowers about 6 mm wide; pods 

 widely spreading, mostly 7-8 cm long, about 1 mm wide in no. 2 of 

 2917. Sisymbrium, p. 489. 



Plants not as above. 



Plants with pods and pedicels closely appressed to the stem; pedicels 



