70 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13 



On coarse arid soils in southern Arizona and western Mexico. The 

 densely sericeus variety is here recognized for the race inhabiting north- 

 western Mexico. The species ranges from southwestern United States 

 to Costa Rica. 



SOPHORA TOMENTOSA L., Sp. PI. 373. 1753. 



Sulphur Bay, Clarion Island, March 16, Elmore B4, upper beach. 



Although widely distributed in the tropical littoral of both hemi- 

 spheres, it is not known from the Mexican mainland, so that its pres- 

 ence on Clarion Island is a special problem in distribution. Native 

 peoples make use of the plant for supposed or actual medicinal proper- 

 ties, and it is possible that early seafaring people introduced the plant 

 on Clarion Island. 



Zygophyllaceae 



Tribullus cistoides L., Sp. PL 387. 1753. 



Sulphur Bay, Clarion Island, March 16, Elmore Bl, beach sand. 



Widely distributed through the w^armer parts of America. 

 Euphorbiaceae 



Euphorbia Anthonyi Brge., Erythea 7:7. 1898. 



Braithwaite Bay, Socorro Island, March 18, Elmore C9, a few 

 plants growing in crevices of lava rocks in side of canyon wall. 



A low shrubby plant endemic to the Revilla Gigedo Islands," the 

 type described from San Benedicto. In Standley's "Trees and Shrubs 

 of Mexico" (C.N.H. 23:602) the t^^pe locality is given erroneously 

 as San Benito Island. Dr. Wheeler, who determined the above collec- 

 tions, states that it is atypical, perhaps juvenile. 



Euphorbia cf. californica Benth., Bot. Voy. Sulph. 49, pi. 23B. 

 1844. 



Sulphur Bay, Clarion Island, March 16, Elmore B8, rocky loam on 

 gradual slope, flowers about one-quarter inch across, yellow green. 



The material is insufficient for certain identification. Typical E. cali- 

 fornica has not been reported from these islands and is known only in 

 the California Gulf Region. 



Euphorbia clarionensis Brge., Erythea 7:7. 1898 and Zoe 5:27. 

 1900. 



Sulphur Bay, Clarion Island, March 16, Elmore B6, upper beach 

 in exposed dry sandy soil, flowers white, the white tips with red brown 

 centers. 



Endemic to the Revilla Gigedo Islands. 



