2 BULLETIN 1194, U. S. DEPAxv^.i^XT OF AGRICULTURE. 
"cashaw" (1). It is found also from the southern boundary of i 
Utah and Colorado to Chile, and has been introduced into India and 
South Africa, where it is attracting favorable attention 05). 
The classification of this plant, according to Holsinger (15), is "one 
of the most perplexful questions." Wooton has classified it as Pro- 
sopis juliflora and as P. velutina, the latter being an arboreal form. 
Sargent (18) holds that forms identified as glandulosa (P. glandulosa 
Torr.) and velutina are merely varieties of P. juliflora DC. Accord- 
ing to Piper 4 — 
The mesquites belong to the botanical genus Prosopis, in which there are about 30 
valid species, although many more than this have been proposed. One species occurs 
in Persia and India, one in the eastern Mediterranean region, two in Africa, and the 
rest in America. Argentina is richest in species, 15 occurring in that country. In 
one group of species, the pods are coiled and hence called screw-beans. By some 
botanists these constitute a distinct genus, Strombocarpa. Two species of screw- 
beans occur in the United States and four in Argentina. The species of Prosopis here 
considered include P. juliflora, described from the West Indies, P. chilensis ^Molina) 
Stuntz, originally described from Chile, and P. glandulosa and P. velutina of the south- | 
western United States. P. juliflora is apparently the same as the older P. chilensis, 
which ranges from Patagonia to Texas. It was also introduced into the Philippines, 
where it was considered a distinct species and called P. vidaliana. P. glandulosa 
is the common mesquite of the Southwest and some botanists consider it a variety of 
P. chilensis (P. juliflora). P. velutina is a relatively rare plant of the Southwest and 
by Sargent is considered a pubescent variety of P. juliflora. In this paper the three 
(chilensis, glandulosa, and velutina) are treated as distinct species. The species so 
abundantly introduced into the Hawaiian Islands is P. chilensis and is there known as 
"kiawe" or ''algaroba." This last name is merely the Spanish name of the carob, 
which has been transferred to somewhat similar leguminous trees, but its use for other 
than the true carob should be discouraged. In the West Indies the native mesquite 
is called " cashaw." The common species in the United States (P. glandulosa Torr.) 
occurs from southern California to Texas and Oklahoma. In modern times it has 
spread greatly and now occupies extensive areas formerly prairie. This is probably 
due to the seeds being carried by horses and cattle and not being injured in passing 
through the intestinal tract. 
The form of P. glandulosa varies greatly, ranging from that of a 
handsome shade tree, attaining a height of 65 feet in favorable 
regions near Tucson, Ariz., to a scrubby bushlike growth, usually 
with an enormous development of the root system. The appearance 
of the fruit or pods from the southwestern United States varies 
somewhat with the region in which the beans are grown (Plates I and 
II). Pods from the Jornada Range Reserve in southwestern New 
Mexico (Plate I) , reported as coming from bushes noticeably different 
in appearance, were of two distinct varieties. The long slender pods 
were creamy white, while the others were streaked with dark red or 
purple which gave them a rusty cast. The appearance of the mesquite 
beans from Yuma, Ariz., (PI. II, fig. 2) is not typical because of 
breakage. 
After a favorable season the quantities of mesquite beans avail- 
able over large areas of southwestern United States are limited only 
by the facilities for gathering the ripe fruit. Wilson (25) states that 
in southern New Mexico it is not uncommon to see a medium-sized 
bush, with a spread of not more than 14 to 18 feet, bearing from 1 
to H bushels of beans. Although the process of gathering the 
fruit is tedious, during the 1917 season it could be secured for from 
20 to 30 cents per 100 pounds. A native worker at the New Mexico 
Agricultural Experiment Station gathered about 175 pounds of dried 
< Unpublished communication from C V. Piper, May, 1923. 
