MUSTARD FAMILY 103 



Pods almost terete, slightly compressed, tapering into a style more than 2 mm. 



long. 4. C. arida. 



Pods 4-angled; style only slightly narrower, very short. 



Basal leaves, as well as whole plant, grayish-strigose, not silvery. 



Pods widely spreading, 4-8 cm. long, stout; stem-leaves usually sinuate- 

 dentate. 5. C. aspera. 

 Pods strongly ascending or almost erect, 8-12 cm. long (except in C. 

 brachycarpa). 

 Stem-leaves usually sinuately dentate. 6. C. elata. 

 Stem-leaves entire or rarely denticulate. 



Stem-leaves linear or nearly so; pod usually twisted, slender. 



7. C. asperruna. 

 Stem-leaves oblanceolate ; pod straight, stout. 



Pod about 8 cm. long, 1.5 mm. thick. 8. C. oblanccolata. 

 Pod 4-6 cm. long, 2.5 mm. thick. 9. C. brachycarpa. 



Basal leaves, at least, silvery white; stem-leaves narrowly linear. 

 Plant 2-3 dm. high; stern-leaves sinuate-dentate. 



10. C. Bakeri. 

 Plant 1-2 dm. high; stem-leaves entire. 11. C. argillosa. 



Low cespitose perennials. 



Leaves entire-margined or minutely denticulate. 12. C. nivalis. 



Leaves sinuate-dentate. 13. C. radicata. 



Petals varying from orange to brown or purple. 



Plant simple, 3-5 dm. high; basal leaves 5-10 cm. long, oblanceolate. 



14. C. Wheeleri. 

 Plant cespitose, 1-2 dm. high; basal leaves 2-4 cm. long, spatulate. 



Perennial with a branched caudex; stem usually more than 1 dm. high. 



15. C. amoena. 

 Biennial; stem in flower a few cm. high, more elongate in fruit, leafy only at 



the base. 16. C. Pallasii. 



26. HESPERIS (Toum.) L. Dame's Rocket, Dame's Violet. 



1. H. matronalis. 



27. CAMPE Dulac. Winter Cress, Scurvy Grass. 

 Pod obtusely angled; leaves with 1—4 pairs of divisions. 



Divisions of the basal leaves 1-2 small pairs; pod slender, ascending. 



1. C. americana. 

 Divisions of the basal leaves 3-4 pairs; pod stouter, erect and appressed. 



2. C. stricta. 

 Pod sharply 4-angled; leaves with 4-8 pairs of divisions. 3. C. verna. 



28. RAPHANUS L. Radish. l. R. sativus. 



29. SINAPIS L. Mustard, Charlock. 



Beak sword-.shaped, constituting more than half the length of the pod. 1. S. alba. 



Beak somewhat 4-angled, but flattened and 2-edged, constitucing about one-third the 

 length of the pod. 2. S. arvensis. 



30. ERUCA (Toiirn.) Mill. Garden Rocket. i. E. Eruca. 



31. BRASSICA L. Cabbage, Rape, Turnip, Black Mustard. 



None of the leaves clasping. 



Pod slender, 4-angled, erect, appressed to the stem. 1. B. nigra. 



Pod ascending, terete, but with a strong midvein. 2. B. juncea. 



Upper stem-leaves clasping. 



Leaves glaucous, all glabrous except the very earUest ones; petals cream-colored, 

 long-clawed. 3. B. campestris. 



Leaves not glaucous, the basal ones distinctly hairy; petals bright yeUow, short- 

 clawed. 4. B. Rapa. 



32. ATHYSANUS Greene. l. A. pusillus. 



33. THYSANOCARPUS Hook. 



Pods pubascent; plant glabrous and glaucous. 1. T. trichocarpus. 



Pods glabrous. 



Plant more or less hirsute; pod entire-margined, fenestrate, or with thin round 

 areas. 2. T . elegans. 



Plant glabrous ; pod toothed, rarely with fenestrations or thin areas. 3. T. amplectens. 



34. ALYSSUM L. Alyssum, Sweet Alyssum. l. A. alyssoides. 



35. BERTEROA DC. Hoary Alyssum. l. B. incana. 



36. IDAHOA Nels. & Macb. Flat-pod. l. I. platysperma. 



37. DENTARIA L. Toothwort, Milk Maids. l. D. rupicola. 



