16 CRUCIFER^. (mustard FAMILY.) 



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



cumbeut. Anthers short, oblong. Leaves lyrately-pinnatifid. 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, 

 ■t- -t- ^^- Pod oblong-cylindric to globose ; valves strongly convex, nerveless; seeds in 2 

 rows, cotyledons accumbent.i 



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 Avinged. 

 H- 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. 



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

 (mostly incumbent in Lepidium) : flowers white. 



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



aliiiiie perennial with entire leaves. 



18. L.epidium. 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. Phy.«aria. Pod didymous ; cells nearly globular. Stellate-canescent perennials with 



entire leaves. 



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



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



dilated or conical, nearly sessile. 



1. DRABA, L. Whitlow-Grass. 



Sepals equal. Filaments mostly flattened, without teeth anthers rounded 

 or oval. — Leaves entire or toothed. 



* Sfe7ns 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 Teto.n 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 narrowlji 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, Kegel. Scape naked or with a single leaf, glabrous : 

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



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

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



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

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



