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



More common than C. humilis, especially in central and northern 

 Arizona. Intergrades with that species, but most of the specimens 

 are readily distinguishable. 



3. Calliandra schottii Torr.'ex S. Wats., Amer. Acad. Arts and Sci. 



Proc. 20: 364. 1885. 



Anneslia schottii Britt. and Rose, North Amer. Fl. 23: 67. 

 1928. 



Pima County, especially in the Santa Catalina and Baboquivari 

 Mountains, 3,000 to 5,000 feet, rocky slopes, ascending to the pinyon 

 belt, August. Southern Arizona and northern Mexico. 



Stems much-branched, up to 1.2 m. high. It is reported that the 

 root system is extraordinarily well developed and that the stems are 

 often frozen back, but the plants soon recover. 



4. Calliandra eriophylla Benth., London Jour. Bot. 3: 105. 1844. 



Anneslia eriophylla Britton, N. Y. Acad. Sci. Trans. 14: 32. 

 1894. 



Greenlee County to Yavapai County, south to Cochise, Santa Cruz, 

 Pima, and Yuma Counties, 5,000 feet or lower, very common on dry 

 gravelly slopes and mesas, February to May. Western Texas to 

 southeastern California and Mexico. 



A straggling shrub, up to 1.2 m. high. 



2. LYSILOMA 



A large, spreading, unarmed shrub with dense foliage; leaves large, 

 with numerous pinnae and many leaflets; flowers in heads, white; 

 stamens very numerous; pods large, flat. 



1. Lysiloma thornberi Britt. and Rose, North Amer. Fl. 23: 83. 1928. 



Pima County, on rock ledges along Chimney Creek in the foothills 

 of the Rincon Mountains, about 3,500 feet, May and June, type 

 collected by Thornber in 1926. Known only from the type locality. 



A very rare and handsome shrub with hard, brittle, dark-brown 

 wood and feathery canopied foliage, well worth cultivating as an 

 ornamental. As seen by the writers at Chimney Creek, it has the 

 appearance of being very long lived and occasionally frozen back. 



3. ACACIA 



Plants shrubs, small trees, or sometimes nearly herbaceous, spiny 

 or unarmed; flowers whitish to bright yellow; stamens numerous. 



Several of the Arizona species, especially the nearly herbaceous A. 

 hirta, are browsed by cattle and horses, and the pods are eaten with 

 relish. 



Key to the species 



1. Inflorescence racemose or spicate; corolla and stamens ochroleucous or cream- 

 colored; pods flat or compressed, thin-walled, oblong, 15 to 20 mm. wide; 

 small trees or large shrubs: Section Senegalia (2) . 

 2. Branches unarmed or bearing slender, straight spines; pinnae 5 to 12 pairs; 

 leaflets very numerous, linear, cuspidate, usually glabrous or merely 

 ciliolate; pods very flat, not twisted or torulose__, 1. A. millefolia. 



