16 CRUCIFER^E. (MUSTARD FAMILY.) 



10. Barbarea. Pod somewhat 4-angled, pointed. Seeds oblong ; cotyledons nearly ac- 



cumbent. Anthers short, oblong. Leaves lyrately-phmatifid. A smooth marsh 

 perennial 



11. Sisymbrium. Pod nearly terete, short-pointed or obtuse. Seeds oblong; cotyle- 



dons incumbent. Anthers linear-oblong, sagittate. Mostly annual, with finely dis- 

 sected or entire leaves. 



12. Smelowskia. Pod short, 4-angled, pointed at each end. Alpine perennials with 



narrowly pinnatifid leaves ; otherwise as Sisymbrium. 



- 4- -- Pod oblong-cylindric to globose ; valves strongly convex, nerveless ; seeds in 2 

 rows, cotyledons accumbent.l 



13. Nasturtium. Pod oblong or short-linear. Flowers white or yellow. Smooth or 



somewhat hispid. 

 11. Vesicaria. Pod ovate to globose. Seed flattened. Flowers yellow. Densely stellate- 



canescent. 

 # # * Pod more or less flattened contrary to the partition, which is narrower than the valves ; 



seeds not winged. 



i- Valves 1-nerved or obtusely carinate, not winged ; cells several-seeded ; cotyledons in- 

 cumbent : flowers white. 



15. Subularia. Pod ovoid, slightly compressed. A dwarf stemless aquatic, smooth, 



with tufted subulate leaves. 



16. Capsella. Pod obcordate or oblong, much compressed. Nearly smooth annuals. 



*- - Valves acutely carinate or winged ; cells few (1 to 5)-seeded ; cotyledons accumbent 

 (mostly incumbent in Lepidium) : flowers white. 



17. Thlaspi. Po^d cuneate-oblong ; valves sharply carinate ; cells 2 to 4-seeded. A smooth 



alpine perennial with entire leaves. 



18. Lepidium. Pod orbicular or obovate, 2-winged at the summit; cells 1 to 2-seeded. 

 --- Valves inflated, nerveless ; cells several-seeded ; cotyledons accumbent : flowers 



yellow. 



19. Physaria. Pod didymous ; cells nearly globular. Stellate-cancscent perennials with 



entire leaves. 



II. Pod of 2 indehiscent cells, separating at maturity from the persistent axis. 8 



20. Biscutella. Cells flat, nearly orbicular, 1-seeded. Flowers rather large. Stigma 



dilated OT conical, nearly sessile. 



1. DRAB A, L. WHITLOW-GRASS. 



Sepals equal. Filaments mostly flattened, without teeth : anthers rounded 

 or oval. Leaves entire or toothed. 



* Stems scape-like, leafless (or perhaps 1 or2-leaved). 



1. D. Stellata, Jacq. Scape with a single leaf, pubescent: leaves oblong- 

 oval, tomentose with a short stellate pubescence : flowers white : pedicels puberulent : 

 pods oblong. Uinta and Teton Mountains, and far northward. 



Var. nivalis, Regel. Scape naked or sometimes with one or two leaves, 

 pubescent : leaves oblanceolate to obovate, canescent with a stellate pubescence : 

 pods narrowl/i oblong, and, with the pedicels, becoming glabrous. D. nemorosa, 

 var. alpina, of the Fl. Colorado. High peaks about Mt. Lincoln, Colorado, 

 and in Arctic America. 



Var. Johannis, Regel. Scape naked or with a single leaf, glabrous : 

 leaves ovate, with a shoi't woollij pubescence : pods long, linear, and with the pedi- 



1 Camelina, an introduced genus, is distinguished by its pear-shaped pod, 1-nerved valves, 

 incumbent cotyledons, and small yellow flowers. See foot-note, p. 25. 



2 Raphanus, an introduced genus, is known by its elongated 1-celled or transversely- 

 jointed pod, which is attenuated above. See foot-note, p. 27. 



