328 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Stamens 5 or 10, distinct. 



Flowers 5-merous; anthers tipped with a gland; 

 pods indehiscent; large shrubs. 



Pods spirally coiled; flowers yellow 3. Strombocarpa (p. 329). 



Pods elongated, not coiled; flowers greenish .. . 4. Prosopis (p. 330). 

 Flowers 4 or 5-merous; anthers not gland-tipped; 

 pods dehiscent; shrubs or herbs. 

 Leaves sensitive; pods more or less 4-sided; 



plants decumbent 5. Morongia (p. 330). 



Leaves not sensitive or at most very tardily so; 

 pods flat; plants erect or spreading, not 

 decumbent. 

 Plants without spines; stems mostly herba- 

 ceous 6. Acuan (p. 330). 



Plants armed with numerous short re- 

 curved triangular spines; shrubs 

 with woody stems 7. Mimosa (p. 331). 



1. CALLIANDRA Benth. 



Low herbaceous or woody perennials without spines, 30 cm. high or less; flowers in 

 globose heads; corolla gamopetalous, elongate-tubular; stamens numerous, monadel- 

 phous, long-exserted ; pods flattened, straight or slightly curved, the valves elastically 

 revolute from apex to base. 



KEY TO THE SPECIES. 



Stems woody throughout 1. C. eriophylla. 



Stems herbaceous, sometimes woody at the base. 



Leaflets 2 or 3 mm. long, pilose; pinnae 4 or more pairs 2. C. humilis. 



Leaflets 5 to 10 mm. long, glabrous or nearly so; pinnae 1 or 2 



pairs 3. C. reticulata. 



1. Calliandra eriophylla Benth. Lond. Journ. Bot. 3: 105. 1844. 



Calliandra chamaedrys Engelni. in A. Gray, Mem. Amer. Acad. n. ser. 4: 39. 1849. 

 Type locality: "Mexico; Chila in the district of Pueblo." 

 Range: Western Texas to Arizona, south into Mexico. 

 New Mexico: Southern Grant County. 



2. Calliandra humilis Benth. Lond. Joum. Bot. 5: 103. 1846. 



Calliandra f herbacea Engelm. in A. Gray, Mem. Amer. Acad. n. ser. 4: 39. 1849. 



Type locality: Zacatecas, Mexico. 



Range: New Mexico and Arizona to Mexico. 



New Mexico: Mogollon Mountains; Kingston; San Luis Mountains; Santa Rita; 

 Sandia Mountains. Dry hills, in the Lower and Upper Sonoran zones. 



The type of C. herbacea was collected by Fendler between San Miguel and Las 

 Vegas. 



3. Calliandra reticulata A. Gray, PI. Wright. 2: 53. 1853. 



Type locality: Stony hills at the Copper Mines, New Mexico. Type collected 

 by Wright (no. 1045). 



Range: Southern New Mexico and Arizona to Mexico. 



New Mexico: West Fork of the Gila; Santa Rita. Dry hillsides. 



2. ACACIA L. Acacia. 



Shrubs or low trees with armed or smooth stems and numerous very small leaflets; 

 flowers small, regular, in spikes or heads on axillary peduncles; corolla valvate, of 4 

 or 5 similar petals; stamens numerous, distinct, exserted; pods flattened or terete, 

 2-valved, dehiscent. 



