88 



BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Other striking plants of the Dog Mountains are 

 (Linnseus) 



rupestris 



(Scheele) 



Engel- 



Jatropha macrorhiza Bentham. 



Rhus irilobata Nuttall. 



Rhus microphylla Engelmann. 



Zieyphus sp. 



Vitis arigonica Engelmann. 



Cereus pectinatus rigidissimus 



mann. 

 Opimtia lindheimeri Engelmann. 

 Opuntia flUpendula Engelmann. 

 Opuntia arborescens Engelmann. 

 Lyoium pallidum Miers. 

 Anisacanthus thurheri Gray. 

 CueurMta fcetidissima Humboldt, 



Bonpland, and Knuth. 

 Ibervillea lindheimeri (Cognlaux) 



Greene. 

 Baccharis pteronioides de Candolle. 

 Baccharis glutinosa Persoon. 

 Crassitia grandiflora (Nuttall) Kuntze. 

 Perezia nana Gray. 

 Trixis angustifolia de Candolle. 



Selaginella 



Spring. 

 Yucca iaccata Torrey. 

 Dasylirion sp. 

 Agave palmeri Engelmann. 

 Nolina Undheimeriana 



Watson. 

 Anemopsis calif ornica Hooker and Ar- 



nott. 

 Argemone mexicana Linnaeus. 

 Fallugia paradoxa(D. Don) Endlicher. 

 Mimosa Muncifera Bentham. 

 Acacia flliculoides (Cavanilles) Tre- 



lease. 

 Acacia oonstricta Bentham. 

 Oassia wisUeeni Gray. 

 Astragalus mollissimus Torrey. 

 Astragalus nuttalUanus de Candolle. 

 Krameria secundiflora de Candolle. 

 Fouquieria splendens Engelmann. 

 Covillea tridentata (de Candolle) 



Vail. 



Station No. 16. — Whitewater, Chihuahua, Mexico. This camp 

 was located on the south side of an arroyo, in which a shallow well 

 supplied us with very bad water, about a mile south of Monument 

 No. 61 and 246 kilometers (153 miles) from the Rio Grande, at an 

 altitude of 1,528 meters (5,013 feet), in the midst of the Whitewater 

 Hills, between the East and West Playas. In September, 1893, the 

 Whitewater arroyo contained water. Animal and plant life were 

 abundant, and large collections were made. I occupied this station 

 May 30 and 31, June 2 and 3, June 13 to 22 and 27 to 29, 1892 ; Sep- 

 tember 10 to 15 and 23, 1893. Mr. Holzner was there June 13 to 22 

 and 27 to 29, 1892. 



Vegetation. — There were no forests in the immediate vicinity of 

 the station, the only trees being small mesquites and a few straggling 

 oaks, hackberry, mulberry, and wild china trees, together with the 

 desert yucca. On the neighboring East Playas and West Playas 

 valleys were extensive tracts occupied by mimosa and creosote bushes, 

 with the tapioca {Jatropha macrorhiza Bentham) and several kinds 

 of gourd {Cucurbita fcetidissima Humboldt, Bonpland, and Kunth; 

 G. digitata Gray; Apodantkera undulata Gray, and a species of 

 Ihervillea) in abundance. The plain and grassy hills surrounding 

 White Water abound with aloe, Nolina or bear-grass, Dasylirion^ 

 yucca, acacia, senna, sumach, Fallugia, Trixis, and numerous species 

 of cacti, among which are Opuntia TOacrocera^?"* Engelmann, 0. arhor- 

 escens Engelmann, and the beautiful rainbow cactus {Cereus pecti- 

 natus rigidissimus Engelmann. 



