24 CKUCIFER^E. (MUSTARD FAMILY.) 



12. SMELOWSKIA, C.A.Meyer. 



Dwarf alpine perennials, distinguished from Sisymbrium by the short 

 4-angled pods. 



1. S. calycina, C. A. Meyer. Densely white-tomentose to nearly gla- 

 brous, cespitose, the much-branched rootstock thickly covered with the shoath- 

 ing bases of dead leaves : leaves mostly radical and with long slender petioles, 

 pinnate or pinnatifid ; segments linear to oblong : pod beaked with a short 

 style and broad stigma, ascending on spreading pedicels : seeds in one row. 

 From Colorado to California and Oregon, and northward. 



13. N A S T U R TI U M, R. Br. WATEK-CRESS. 



Growing in water or in moist places, smooth or nearly so, with the leaves 

 pinnatifid or lyrate. 



* Flowers small, yellow or yellowish. 



1. N. ObtUSUin, Nutt. Glabrous or nearly so: stems much branched: 

 leaves pinnately parted or divided, often lyrate, decurrent; segments oblong- 

 roundish, obtusely toothed or repand : racemes elongated in fruit : pods ovate 

 to linear-oblong, twice the length of the pedicels ; style short. From Colorado 

 to the headwaters of the Yellowstone and eastward. Growing in the spray of 

 the Lower Falls of the Yellowstone. 



Var. (?) alpinum, Watson. Dwarf: leaves oblong, entire or with a few 

 teeth or coarsely lyratc-pinnatifid : pods mostly shorter than the pedicels. Bot. 

 King's Exp. 15. Uinta Mountains. 



2. N. palustre, DC. Stout, glabrous, erect, 1 to 3 feet high: leares 

 lanceolate, lyrately-pinnatijid, petioled : pods oblong, equalling the spreading 

 pedicels, tipped by the prominent style. E. California to Colorado, thence 

 northward and eastward. 



Var. hispidum, Fisch. & Meyer. Somewhat hispid : pods shorter, globose- 

 oblong. The more common form. 



3. 3ST. CUrvisiliqua, Nutt. Smooth, usually erect, % to 1 foot high : 

 leaves narrowly oblong or oblanceolate, pinnatijid with oblong usually toothed lobes, 

 rarely only sinuate-toothed : pods rather slender on pedicels of about the 

 same length, both often strongly curved; style prominent or none. W. Wyo- 

 ming and Idaho to Washington Terr, and California. 



4. N. sinuatum, Nutt. Stems diffuse, slender, decumbent, smooth or 

 slightly roughened, from perennial creeping or subterranean shoots : leaves 

 lanceolate, usually narrow, regularly sinuate-pinnatifid with numerous linear- 

 oblong nearly entire lobes : pods linear, tipped with the long style, becoming 

 curved, as also the slender pedicel. From New Mexico to the Upper Missis- 

 sippi and westward to the Sierra Nevada. 



* * Flowers whiteJ- 



5. N. trachycarpum, Gray. Nearly glabrous, erect, branching: 

 leaves lyrate-subpinnatifid : pods oblong-linear, papillose-roughened, curved- 



1 N. officinale, R. Br., is a smooth procumbent aquatic rooting at the joints, with pinnate 

 leaves and sinuate leaflets, and with spreading pedicels and a short thick style. Intro- 

 duced in the streams about Denver and Salt Lake City, and doubtless elsewhere. 



