MUSTARD FAMILY 



II. Pods oblong to linear, more than twice as long as 

 wide 



1. Pods strongly flattened 



a. Weeds with cream or yellowish flowers and 



pinnatifid leaves Sisymbrium 



b. Natives with white to pink flowers, if yellow 



the leaves not pinnatifid 



( 1 ) Anthers arrow-shaped at base ; leaves usu- 



ally clasping Streptanthus 



(2) Anthers not arrow-shaped 



(a) Pods less than 2 cm. long Draba 



(b) Pods 2-8 cm. long 



x. Pods 1-nerved on each face Arabis 



y. Pods without a distinct nerve or rib on 



each face Cardamine 



2. Pods 4-angled or round in section 



a. Pods round in section 



(1) Pods closed when ripe; weed Raphanus 



(2) Pods splitting when ripe 



(a.) Pods distinctly stalked in or above the 

 calyx 

 x. Stamens long-exserted Stanleya 



y. Stamens included 



(x) Petals flat Thelypodium 



(y) Petals wavy-margined Caulanthus 



(b) Pods not stalked above the calyx 

 x. Pods with a beak 3-15 mm. long Brassica 



y. Pods not beaked 



(x) Seeds few Smelowskia 



(y) Seeds many 

 m. Leaves finely dissected Sophia 



n. Leaves pinnatifid, but not finely 

 dissected 

 (m) Seeds in 1 row in each half of 



the pod Sisymbrium 



(n) Seeds in 2 rows in each half Roripa 



b. Pods 4-angled 



(1) Pods stalked in or above the calyx Thelypodium 



(2) Pods not stalked 



(a) Flowers white or cream-colored 



