16 MUSTARD ORDER 



BRASSICACEAE MUSTARD FAMILY 



Sepals 4, petals 4, rarely none, separate, usually with a claw, stamens 

 usually 6, 2 shorter, rarely 1-4, ovary 2-celled, style 1, stigma entire or 2- 

 lobed, fruit a pod, usually 2-celled and many-seeded ; flowers in racemes or 

 corymbs; herbs with alternate simple, rarely compound leaves. 

 I. Pod round, globose or triangular to short-oblong 

 1. Pods flattened 



a. Pods of 2 round halves, resembling spectacles DITHYREA 



b. Pods round to ovoid or oblong 



(1) Seeds single in each half; pods round to 



short-oblong LEPIDIUM 



(2) Seeds 2-many in each half 



(a) Pods round, winged or margined 



x. Pods winged all around; flowers white 



or purplish THLASPI 



y. Pods margined above; flowers yellow- 

 ish ALYSSUM 



(b) Pods ovoid to elliptic or oblong, not 



winged 

 x. Leaves pinnatifid ; seeds several in each 



cell 

 (x) Flowers 1-2 mm. wide; pods 3-4 HUTCHINSIA 



mm. long 

 (y) Flowers 5-8 mm. wide; pods 6-12 



mm. long SMELOWSKIA 



y. Leaves entire or toothed ; seeds many in 



each cell DRABA 



c. Pods triangular, not winged; leaves pinnatifid BURSA 

 2. Pods round in section or inflated, not flattened 



a. Submerged aquatic; leaves awl-shaped SUBULARIA 



b. Terrestrial 



(1) Pods of 2 inflated cells PHYSARIA 



(2) Pods globose to pear-shaped or oblong, not 



inflated 



(a) Leaves pinnatifid RORIPA 



(b) Leaves entire 



x. Leaves gray with star-shaped hairs; 



pods globose to oblong LESQUERELLA 



y. Leaves green, not stellate-hairy; pods 



pear-shaped CAMELINA 



