CRUCIFERiE. (MUSTARD FAMILY.) 23 



10. BARBAREA, R. Br. Winter Cress. 



Valves somewhat carinate. Seeds in one row, turgid, marginless. — Erect 

 and branching, with angled stems. 



1. B. vulgaris, R. Br. Stem 1 to 3 feet high: lower leaves lvrate- ^ 

 pinnatifid, with a larger rounded terminal lobe and 1 to 5 pairs of lateral 

 ones ; upper leaves obovate, more or less pinnatifid at base : pods erect, often 

 appressed. — From Oregon eastward. 



11. SISYMBRIUM, 1 L. Hedge Mustard. 



Sepals scarcely gibbous at base. Seeds not margined. — Erect herbs, with 

 small flowers, the leaves not clasping or auriculate, rarely entire. 



* Leaves pinnate or bipinnate. 



1. S. canescens, Nutt. Canescent icith short branching hairs: stems 

 £ to 2^ feet high : leaves 1 to 2-pinnate, with the segments more or less deeply 

 pinnatifid or toothed : pods acute at each end and pointed with the very short 

 style, shorter than the slender spreading pedicels : seeds in two rows. — Very 

 common on the plains and in the mountains. From Colorado to Arctic 

 America, westward to California, and eastward to New York and Pennsyl- 

 vania. 



2. S. incisum, Engelm. Pubescence short, more or less glandular : stems 

 1 to 4 feet high : leaves pinnate, with the segments linear to ovate-oblong, 

 more or less deeply pinnatifid, sometimes entire : pods pointed at both ends, 

 mostly exceeding the spreading pedicels : seeds in one row. — S. Californicum, 

 Watson in Bot. King's Exp. 23. Oregon and Washington, eastward to Win- 

 nipeg Valley and southward to New Mexico. 



* * Leaves entire or toothed. 



3. S. glaucum, Nutt. Glaucous, about 1 foot high: radical leaves 

 small, spatulate ; cauline ovate, sagittate and clasping, rather acute : flowers 

 very small, pale purple : pods erect : seeds in one or two rows. — South Park. 

 Colorado, and northwestward to Oregon. 



4. S. Virgatum, Nutt. Canescently hirsute with simple and stellate hairs: 

 stem about a span high, virgately branched from the base : leaves lanceolate- 

 linear, clasping ; lower ones denticulate or entire : flowers larger, pale purple : 

 pods erect : seeds in hoo rows. — On the Platte and its tributaries. 



5. S. linifolium, Nutt. Glabrous and glaucous, 1 to l£ feet high: leaves 

 narrowly obi a nceol ate or linear : flowers light yellow: pods ascending on short 

 spreading pedicels, with short thick styles: seeds in one row. — S. junceum of 

 Hayd. Rep. 1871, 1872. W. Wyoming and northwestward through Montana 

 and Idaho. 



1 Brassica is an allied genus, represented in our range by the following introduced 

 species : — 



B. Sinapistrum, Boiss. Known by its rough spreading hairs, lower lpaves usually with a 

 large coarsely toothed terminal lobe, upper leaves often undivided, and the pods more than 

 a third occupied by the stout 2-edged beak. —Around settlements in S. Montana and Idaho, 

 and undoubtedly elsewhere. 



