62 MUSTARD FAMILY. 



A. hirsuta, Scop. HAIRY R. Mostly rough hairy, l-2 high ; stem- 

 leaves many and sagittate ; pedicels of the small greenish-white flowers 

 and the pods strictly erect ; style almost 0. Rocks, N. 



*- -i- - Erect, leafy-stemmed l-3 high; leaves simple; pods 3'-4' long, 

 recurved or hanging ; seeds broadly winged. 



A. laevigata, Poir. SMOOTH R. Smooth and glaucous ; upper leaves 

 sagittate and clasping ; petals scarcely as long as calyx ; pods very narrow 

 and not very flat, recurving. 



A. Canadensis, Linn. SICKLE POD. Stem-leaves pointed at both ends, 

 pubescent ; petals twice as long as calyx ; pods scythe-shaped, very flat, 

 hanging. 



* * Flowers showy, white in spring ; garden species from Eu. % 

 A. alplna, Linn. ALPINE R. Low and tufted, hairy or soft-downy ; 



lower leaves oblong-obovate, sharply toothed ; petals gradually narrowed 



to a claw. 



A. dlbida, Stev. Leaves sparingly toothed; petals abruptly narrowed 



into a claw. 



2. Seeds in 2 more or less distinct rows, at least when young ; strict 

 and very leafy- stemmed. 



A. perfol&ta, Lam. TOWER MUSTARD. 2-4 high, glaucous ; petals 

 yellowish-white, little longer than calyx ; pods and pedicels strictly erect. 

 N. Eng. to Minn., N. and W. (g) 



A. conflnis, Wats. Scarcely glaucous ; petals white or rosy, twice 

 length of calyx ; pods loosely erect to spreading. Canada, S. to Conn., 

 W. to Minn, and 111. (2) 



3. Seeds in 1 row, very small, wingless. 



A. lyrata, Linn. Low R. Delicate, low, nearly smooth, root-leaves 

 lyrate ; stem-leaves few and narrow with a tapering base ; bright white 

 petals rather conspicuous ; pods slender, spreading, @ 11 



A. dentata, Torr. & Gray. Roughish pubescent ; root-leaves oblong, 

 toothed ; stem-leaves half-clasping and eared at base ; pods widely spread- 

 ing. N. Y. to Mich., Minn, and S. (2) 



7. DRAB A, WHITLOW GRASS. (Greek : the name of some cress 

 meaning unknown.) Low herbs, mostly with white flowers ; pods round- 

 oval, oblong or linear, flat. Elowers early spring. Winter annuals. 



* Pods longer than their pedicels; leaves obovate. 



D. Caroliniana, Walt. Leaves entire, hairy, on a very short stem, 

 bearing a short raceme or corymb on as cape-like peduncle l'-4' high ; 

 petals not notched ; pods broadly linear, smooth ; in sandy waste places. 



D. cuneif61ia, Nutt. Leaves toothed ; raceme elongated (l'-3') in 

 fruit ; petals notched ; pods oblong-linear, hairy. 111. to E. Kan. and S. 



D. verna, Linn. Leaves all radical, oblong or lanceolate ; scape l'-3' 

 high ; petals white, 2-cleft ; pods oval or oblong ; in sandy waste places. 

 Introd. from Eu. 



* # Pods equaling or shorter than their pedicels ; leaves oblong to lanceo- 

 late. 



D. brachycarpa, Nutt. Stems leafy, 2'-4' high ; flowers yellow ; 

 petals minute or ; pods smooth. Va., W. 



8. ALYSSUM. (Greek name of a plant.) Cult, for ornament. 



A. maritimum, Lam. SWEET ALYSSUM. Spreading, green or slightly 

 hoary ; leaves lanceolate or linear entire, tapering at the base ; flowers 



