16 CRUCiFERiE. (Mustard family.) 



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



cumbent. Anthers short, oblong. Leaves lyrately-pinnatiflrl. 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 iinely dis- 

 sected or entire leaves. 



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



narrowly pmnatifid leaves ; otherwise as Sisymbrium. 

 4~ «t- ■*- Pod oblong-cylindric to globose ; valves strongly convex, nerveless ; seeds in 2 

 rows, cotyledons accumbent. 1 



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



somewhat hispid. 



14. 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, 

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

 cumbent : flowers white. 



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



with tufted subulate leaves. 



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



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

 (mostly incumbent in L&pidium) : flowers white. 



17. Thlaspl. Pod cuneate-oblong ; valves sharply carinate ; cells 2 to 4-seeded. A smooth 



alpine perennial with entire leaves 

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

 •i- -i- ■*- Valves inflated, nerveless ; cells several-seeded ; cotyledons accumbent : flowers 



yellow. 



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



entire leaves. 



IT. Pod of 2 indehiscent cells, separating at maturity from the persistent axis. 3 



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



dilated or 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 or 2-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, Kegel. Scape naked or sometimes with one or two leaves, 

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

 pods narrowljf oblong, and, with the pedicels, becoming glabrous. — D. nemorosa, 

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

 and in Arctic America. 



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

 leaves ovate, with a short woollij pubescence : pods long, linear, and with the peai- 



1 Camelina, an introduced genus, is distinguished by its pear-shaped pod, 1-nervcd 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. 



