286 CALIFORNIA ACADEMY OF SCIENCES. 



seeded, the rest three-seeded. It was startling to find 

 this plant with Ampeloftst's quinquefolia and Adiantum 

 capillus-veneris in the midst of sonoran vegetation, where 

 a living spring made an oasis in the desert. It also 

 grows around Willow Creek Spring. 



18. Ampelopsis quinquefolia Michx., Fl. i, 160. 

 Type localities: "Virginia, Canada." 



Collected in flower at Butler Spring and with immature 

 fruit in the canon of the San Juan River, near Willow 

 Creek junction. Its presence along the banks of the San 

 Juan is more easily understood, but at the head of Butler 

 Wash, where all communication with riparian vegetation 

 seems cut off, it is very puzzling. 



19. Rhus Canadensis Marsh., var. simplicifolia Greene, 

 Torr. Bull., xvii, 13. 



Type locality: "In the deep canons of northern 

 Arizona, which lead down to the grand canon of the 

 Colorado." 



This grew with the typical form on the sandy flats 

 of the San Juan River, near Bluff City. The Utes 

 use the red berries to make an acid drink, and the com- 

 mon name through that region is " Ute lemonade." 



20. Psoralea micrantha Gray, Pac. R. R. Rep., iv, 77 

 (1856). 



Type locality: "Last Camp on the Canadian," Indian 

 Territory. 



Common along the sand flats of the San Juan River, 

 near Bluff City. 



21. Psoralea juncea n. sp. Plate xliv. 



Perennial, in clumps, 6 to 9 dm. high and about 9 dm. 

 in diameter, with numerous slender virgate branches, 

 glabrous except for scattered, small, white, appressed hairs, 

 most numerous at the nodes; stems indistinctly ribbed, 



