418 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



1. Mimosa laxiflora Benth., London Jour. Bot. 5: 93. 1846. 

 Known in Arizona only from near Quijotoa and Sells, Papago Indian 



Reservation, western Pima County, about 2,500 feet, rocky slopes and 

 along washes, with Acacia greggii, Cercidium, Simmondsia, Cereus 

 giganteus, etc., August. Southern Arizona and northern Mexico. 



2. Mimosa dysocarpa Benth. in A. Gray, PL Wright. 1: 62. 1852. 

 Cochise, Santa Cruz, and Pima Counties, 3,500 to 6,500 feet, 



commonly along arroyos and washes, July to September. Western 

 Texas to southern Arizona and northern Mexico. 



Arizona's showiest and handsomest Mimosa, with long spikes of 

 purplish pink flowers. Occupying the same region and commoner 

 than the typical form is var. wrightii (A. Gray) Kearney and Peebles 

 (M. wrightii A. Gray), which has the pods normally somewhat nar- 

 rower and unarmed (sparsely prickly in typical dysocarpa) and leaflets 

 glabrous or glabrate above, but the correlation between these char- 

 acters is low. 



3. Mimosa biuncifera Benth., PL Hartw. 12. 1839. 



Mimosopsis biuncifera Britt. and Rose, North Amer. Fl. 23: 

 176. 1928. 



Southern Apache County to -Yavapai County, south to Cochise? 

 Santa Cruz, and Pima Counties, 3,000 to 5,500 feet, dry soil of mesas 

 and rocky slopes, commonly in chaparral, May to August. Western 

 Texas to Arizona and northern Mexico. 



Wait-a-bit, wait-a-minute, often also called "catclaw," but this 

 name belongs properly to Acacia greggii. A common straggling shrub 

 in south central Arizona, reaching, exceptionally, a height of 2.4 m. 

 (8 feet). It often forms dense thickets of considerable extent, making 

 a very efficient soil binder. When other food is scarce it furnishes 

 forage for livestock. It is reputed to be a good honey plant. 



The var. glabrescens Gray, much less pubescent than the typical 

 form, occurs throughout the range of the species in Arizona. 



4. Mimosa grahami A. Gray, PL Wright. 2: 52. 1853. 



Mimosopsis grahami Britt. and Rose, North Amer. FL 23: 

 178. 1928. 



Cochise, Santa Cruz, and Pima Counties, 4,000 to 5,000 feet, dry 

 slopes, April to August, type from "between the San Pedro and the 

 Sonoita" (Wright 1042). Southwestern New Mexico, southeastern 

 Arizona, and northern Mexico. 



About equally common in Arizona are the typical form and var. 

 lemmoni (A. Gray) Kearney and Peebles (Mimosa lemmoni A. 

 Gray), which seems to differ only in the copious pubescence of the 

 herbage, flowers, and pods (these glabrous or sparsely pubescent in 

 typical M. grahami) . Numerous specimens are intermediate. The 

 type of M. lemmoni was collected in the Huachuc v a Mountains (Lem- 

 mon 2692). 



5. DESMANTHUS 



Plants herbaceous or shrubby, unarmed; leaflets very numerous, 

 small; flowers sessile, in axillary heads, whitish; stamens 10; pods 

 slender, elongate. 



