MUSTARD FAMILY 



357 



Leaves not coarsely hirsute; perennials. 



Pubescence, if any, sparse and consisting of 2-forked or rarely 3-forked hairs . 



IV. DRUMMOXDIAXAE. 

 Pubescence of at least the lower leaves decidedly stellate. 



V. MlCROPHYLLAE. 



Pods spreading or reflexed. 



Pods and calyx stellate. VI. PULCHRAE. 



Pods not stellate. 



Pods 3-4 ram. wide. VII. SUFFRUTESCEXTES, 



Pods 1-2.5 mm. wide. 



Pods spreading or somewhat recurved on spreading pedicels. 



Pods only 1-1.5 mm. wide. VIII. MACOUNIANAE. 



Pods 1.52.5 mm. wide. 



Perennials, with a caudex. 



Plant tall, 3 dm. or more high, suffruticose at the base. 



IX. PEREXNANTES. 



Plant low, 1-2 dm. high, cespitose. X. RECOXDITAE. 



Stout biennials or short-lived perennials, 3 dm. high or more. 



XI. ARCUATAE. 

 Pods and pedicels reflexed. XII. RETROFRACTAE. 



I. LYRATAE. 



Pods about 0.75 mm. wide; style more than 0.5 mm. long. 

 Pods fully 1 mm. wide; style almost obsolete. 



1. A. lyrata. 



2. A. ambigua. 



II. FURCATAE. 



Seeds not winged; leaves hairy; pods 1 mm. wide or less. 3. A. Nuttallii. 



Seeds winged at the lower end; leaves merely ciliate on the margins ; pods 1.5-2 mm. wide. 



4. A. furcata. 



III. HlRSUTAE. 



All sepals narrowly oblong; two of them with slightly saccate bases; petals 3-5 mm. long, 

 yellowish white, less than twice as long as the sepals. 5. A. ovata. 



Two of the sepals with strongly saccate bases, almost twice as broad as the others; petals 

 6-10 mm. long, pure white, fully twice as long as the sepals. 6. A. rupestris. 



A. Drummondii. 

 A. conncjca. 



A 

 A 



albertina. 

 Lyallii. 



IV. DRUMMOXDIANAE. 



Stems 3 dm. high or more, solitary or 2 or 3 from the same root. 



Pods about 1.5 mm. wide. 7. 



Pods about 3 mm. broad. 8. 

 Stems less than 3 dm. high, several from a cespitose caudex. 



Pods strictly erect, blunt. 9. 



Pods rather ascending, acute. 10. 



V. MlCROPHYLLAE. 



Stems more than 3 dm. high; basal leaves 3-10 cm. long. 11. A. oblanceolata. 



Stems usually less than 3 dm. high, from a branched caudex; basal leaves 1-2 cm. long. 

 Plant green; petals 78 mm. long; pods fully 2 mm. wide; stem-leaves ovate-lanceolate. 



12. A. oreophila. 

 Plant grayish; petals about 5 mm. long; pods 0.75-1.5 mm. wide; stem-leaves oblong 



or linear, the lower oblanceolate. 

 Flowers few; pods more than 1 mm. wide; seeds somewhat 2-ranked; stem hirsute- 



ciliate below or glabrous. 13. A. microphyUa. 



Flowers many; pods less than 1 mm. wide; seeds strictly in one row; stem finely 

 stellate. 14. A. Crandallii. 



VI. PULCHRAE. 



Seeds distinctly in two rows; stem-leaves not auricled. 



Petals purple, 8-10 mm. long. 



Petals white, 10-12 mm. long. 

 Seeds in one row; stem-leaves more or less auricled; petals 5-8 mm. long. 



Leaves usually coarsely toothed; petals pink, 6-8 mm. long. 17. A. subpinnatifida. 



Leaves entire; petals white, 5-6 mm. long. 18. A. MacDougalii. 



15. A. pulchra. 



16. A. formosa. 



19. A. suffrutescens. 



20. A. drepanoloba. 



VII. SUFFRUTESCEXTES. 



Stems suffrutescent at the base; pods reflexed. 

 Stems not suffruticose; pods spreading. 



VIII. MACOUNIANAE. 



Petals about 4 mm. long; pod 3-4 cm. long; basal leaves 1-2 cm. long. 



21. A. Macounii. 

 Petals about 8 mm. long; pod 4-6 cm. long; basal leaves 4-6 cm. long. 



22. A. arcoidea. 



One species. 



Leaves finely stellate. 



Leaves thick, canescent; stems simple. 

 Pod about 1.5 mm. wide, acute. 



IX. PEREXNANTES. 

 X. RECONDITAE. 



23. A. perennans. 



24. A. Lemmonii. 



