330 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



1. Strombocarpa pubescens (Benth.) A. Gray, PI. Wright. 1: 60. 1852. 



Prosopis pubescens Benth. Lond. Journ. Bot. 5: 82. 1846. 



Type locality: "California between San Miguel and Monterey." 



Range: Western Texas to Arizona and California. 



New Mexico: Socorro; Animas Creek; Mesilla Valley. River valleys, in the 

 Lower Sonoran Zone. 



This is one of the common large shrubs of the river valleys of the southern part 

 of the State, where it is everywhere known under its Spanish name of "tornillo." 

 The larger stems or trunks serve very well for fence posts and the wood is also 

 extensively used for fuel, being the best for this purpose found at the lower levels. 

 The pods contain a large amount of sugar and are very sweet when chewed. 



4. PROSOPIS L. Mesquite. 



A much branched shrub 3 meters high or less, seldom larger, with rigid tough stems 

 bearing large stipular spines; leaves with 1 or 2 pairs of pinnae and numerous oblong 

 entire leaflets; flowers small, greenish yellow, in axillary spikes; fruit an indehiscent, 

 slightly compressed, straight or falcate legume. 



1. Prosopis glandulosa Torr. Ann. Lye. N. Y. 2: 192. 1828. 



Type locality: "On the Canadian?," New Mexico. 



Range: Arizona and New Mexico to Oklahoma and Texas. 



New Mexico: Common from the Black Range to Socorro, and Tucumcari and 

 southward across the State. Plains and river valleys, in the Lower and Upper Sono- 

 ran zones. 



This is one of the best known plants of the arid southwest and in southern New 

 Mexico is of great economic importance. The flowers furnish the best of nectar for 

 honey making. The leaves and pods are eaten by all kinds of grazing animals. The 

 pods, too, on account of their sugar content, are often eaten when ripe by the native 

 people. The large roots and thickened bases of the stems furnish the best fuel of 

 the region. The legumes and seeds were collected by the Indians, who ground 

 them and formed the meal into a sort of bread . 



5. MORONGIA Britton. Sensitive brier. 



Decumbent perennial with recurved prickles on leaves and stems; flowers pink, in 

 a globose head; pod narrow, 4-sided, 4-valved, spiny. 



1. Morongia occidentalis Woot. & Standi. Contr. U. S. Nat. Herb. 16:135. 1913. 



Type locality: Sandy soil at Logan, New Mexico. Type collected by G. L. 

 Fisher (no. 93). 



Range: Known only from type locality. 



6. ACUAN Medic. 



Suffrutescent or herbaceous perennials with unarmed herbaceous stems and numer- 

 ous small leaflets; flowers in axillary pedunculate heads, greenish white; calyx some- 

 times pappiform or wanting; stamens 5 or 10, the anthers not gland-bearing; fruit a 

 flattened dehiscent legume, straight or arcuate. 



KEY TO THE SPECIES. 



Stamens 5; plants tall, erect; pinnae 10 to 14 pairs; pods arcuate, in 



a crowded headlike cluster 1. A. illinoensis. 



Stamens 10; plants low, spreading; pinnae 3 to 6 pairs; pods straight, 



fewer, divaricate 2. A. jamesii. 



Acuan velutina was reported from Santa Rita in the Botany of the Mexican Bound- 

 ary, but the specimens upon which the report is based seem to be A. jamesii. 



