i8 MUSTARD ORDER 



x. Flowers cream-colored ; pods 2-4 in. 



long CONRINGIA 



y. Flowers white; pods 2-3 cm. long STENOPHRAGMA 



(b) Flowers yellow to orange, rarely deep 



red-purple 



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



y. Pods beakless or nearly so 



(x) Leaves entire or toothed ERYSIMUM 



(y) Leaves pinnatifid BARBAREA 



ALYSSUM Linne 1753 YELLOW ALYSSUM 

 (Gr. alysson, a plant used to check hiccup) 



PL 6, fig. 7. 



Sepals 4, petals 4, yellowish or whitish, stamens 6, pod round, flattened, 

 winged, 4-seeded, notched, style short ; flowers in dense racemes ; leaves 

 spatulate to oblong, densely gray stellate-hairy ; low annual. 

 Stems several from the base, hairy ; flowers tiny A. calydnum 



ARABIS Linne 1753 ROCKCRESS 

 (Named for Arabia) 



PL 6, fig. 41-42. 



Sepals 4, petals 4, white to purple, rarely yellowish, stamens 6, pod 

 long, linear, flat, seeds in 1 or 2 rows, style short ; flowers in racemes or 

 corymbs ; leaves entire to pinnatifid ; annual, biennial or perennial. 



1. Pods erect or spreading 



a. All or nearly all the stem leaves smooth 



(1) Lower part of the stem and basal leaves 



hairy or shaggy A. gldbra 



(2) Stem and basal leaves smooth, often 



glaucous A. Drummondii 



b. Stem and leaves usually hairy or ciliate 



throughout A. hirsuta 



2. Pods recurved or hanging A. Holboellii 



BARBAREA Linne 1753 WINTERCRESS 

 (Named for St. Barbara) 



PI. 6, fig. 30. 

 Sepals 4, petals 4, yellow, stamens 6, pod linear, 4-angled, seeds in 



