30 CRUCIFER.ZA. 
1. Barbarea vulgaris, Br. in Ait. Hort. Kew. ed. 2, vol. iv. p. 109. 
North temperate zone, Australia, and S. Africa. The Mexican and North-American 
Boundary Commission collected specimens of this plant; but these may be from Texas 
or New Mexico. We have seen no undoubted Mexican specimens; nor is it enumerated 
in the ‘ Botany of California,’ recently issued by the U.S. Geological Survey. 
3. ARABIS. 
Arabis, Linn. Gen. Plant. n. 18; Benth. et Hook. Gen. Plant. 1. p. 69. 
About 130 species are scattered in botanical works ; but there are scarcely more than 
sixty well defined. The greater part inhabit Europe and North Asia; twelve occur in 
North America; and a few are natives of the southern hemisphere. 
1. Arabis (Turritis) patula, Grah. in A. Gr. Pl. Fendl. i. p. 7. 
Streptanthus virgatus, Nutt. 
Norta AMERICA, through the Rocky Mountains from Lake Winnipeg to—Norru 
Mexico, Sonora (Parry), Lake Santa Maria, Chihuahua (Bigelow). 
2. Arabis, sp. ? 
Sout Mexico, valley of Mexico (Bourgeau, 285). Hb. Kew. 
. 4, DRYOPETALON. 
Dryopetaion, A. Gray, Pl. Wright. ii. p. 12, t. 11; Benth. et Hook. Gen. Plant. i. p. 69. 
The genus is at present limited to the following species :— 
1. Dryopetalon runcinatum, A. Gray, Pl. Wright. ii. p. 12, t. 11. 
Texas and Catirornia to—NortH Mexico, mountains of Chihuahua and Sonora 
(Bigelow, Parry, and Schott). | | 
| 5. STREPTANTHUS. 
Streptanthus, Nutt. in Journ. Acad. Phil. v. p. 134, t. 7; Benth. et Hook. Gen. Plant. i. p. 69. 
A genus of about fifteen species, confined to Western North America. 
1. Streptanthus carinatus, A. Gray, in Proc. Am. Acad. vi. p. 183. 
Catirornta, New Mexico, to—Norta Mexico. Hb. Kew. 
2. Streptanthus cordatus, Nutt. in Torr. & Gray, Fl. N. Am. i. p. 77. - 
CoLoRaDo and CaLirornia to—NortH Mexico, Sonora Pass (‘ Botany of California’). 
3. Streptanthus linearifolius, A. Gray, Pl. Fendl. p. 7. 
New Mexico.—Norta Mexico, Guadaloupe Cafion, Sonora (Thurber), Chihuahua 
(Schott), Lake Santa Maria, Chihuahua (Wright). Hb. Kew. 
4, Streptanthus platycarpus, A. Gray, Pl. Wright. ii. p. 10. 
New Mexico and Texas to—NortH Mexico, Chihuahua and westward to Sonora 
(Bigelow, Parry, and others). | 
