1885.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 499 



Prosopis pubescens, Benth. (Screw Bean; Tornillo.) 



Low, neat shrub, growing luxuriantly along the Rio Grande and 

 many of its tributaries from El Paso to Devil's Eiver. Its straight and 

 long stems are useful for building huts, and fencing. It is also an ef- 

 fective hedge-plant on bottom-lands. The wood is not near as hard as 

 that of Mezquit but makes good fuel. 



The twisted pod, or " beaa," contains a spongy and nutritious pulp 

 rich in sugar, and is used as food by Mexicans and Indians. Herbiv- 

 orous animals are very fond of it. Its smallness, however, and the 

 stony hardness of the seeds render it less valuable than that of the 

 Mezquit. 



Acacia flexicaulis, Ben til. (Mexican Ebony.) 



Shrub, or small round-headed tree, with handsome evergreen foliage, 

 common on the bluffs of the Lower Rio Grande and the Gulf Coast. 

 Its straight trunk is seldom over a foot in diameter. Wood heavy and 

 compact, with the several shades of ebony and taking nearly as fine 

 a polish, hence its great value to cabinet-makers. As fuel it is even 

 considered superior to that of Mezquit. Ebony posts are reputed the 

 most durable of any made from Texas woods and m.iy be said to last 

 forever. 



The thick, woody pods, 4 to 6 inches long, contain round seeds the 

 size of peas, which, if boiled while still green, are quite palatable and 

 nutritious. When ripe and dry they are toasted by the natives and 

 the black outer skin, or testa, used as a substitute for coffee. 



The flowers, in cream-colored catkins, exhale a very delicate fra- 

 grance. 



Acacia Famesi ana, Willd. (Huisache.) 



Spreading, round-headed, ornamental tree, with evergreen (in mild 

 winters) and beautiful foliage; common at San Antonio and thence to 

 the Lower Rio Grande and the Gulf Coast. Trunk seldom over a foot 

 in diameter. The rose-colored wood is hard and compact, excellent for 

 cabinet-work; probably contains tannin; makes very good fuel. Huis- 

 ache posts rank next to thos(^*of Mezquit in durability. 



The yellow, capitate flowers, which appear in great profusion during 

 February and March, are very fragrant and would probably yield a rich 

 essential oil. 



A decoction of the pod contains tannin, and is used by Mexicans who 

 mix it with an iron salt to make writing ink. 



Acacia Greggii, Gray. 



Mere straggling shrub above Laredo, becoming a small, slender tree 

 35 feet high, with stem 8 to 10 inches thick, on the Lower Rio Grande 

 where it is called Una de Gato. Forms most intricate spinose thickets 

 on many gravelly bluffs where it would make excellent hedges. Wood 

 exceedingly hard, close-grained and heavy. 



