548 



TREES OF NORTH AMERICA 



style filiform, with a minute terminal stigma. Legume linear, compressed or sub- 

 terete, straight or falcate, or contorted or twisted into a more or less regular spiral, 

 indehiscent; the outer coat thin, woody, pale yellow, inclosing a thick spongy inner 

 coat of sweet pulp containing the seeds placed obliquely and separately inclosed, 

 their envelopes forming nut-like joints. Seeds oblong, compressed, the hilum near 

 the base; seed-coat crustaceous, light brown, lustrous; embyro surrounded by a layer 

 of horny albumen; radicle short, slightly exserted. 



Prosopis is distributed in the New World from southern Kansas to Patagonia, 

 and in the Old World is confined to tropical Africa, and to southwestern and tropi- 

 cal Asia. Sixteen or seventeen species have been distinguished. Of the three species 

 found in the territory of the United States two are small trees. 



Prosopis produces hard durable wood, particularly valuable as fuel, and the pods 

 are used as fodder. 



The generic name is from irpoawirls, employed by Dioscorides as a name of the 

 Burdock. 



CONSPECTUS OF THE NOKTH AMERICAN ARBORESCENT SPECIES. 



Legume compressed or ultimately convex, pinnae 12-10-foliolate. 1. P.juliflora(C,E,G,H). 

 Legume thick, spirally twisted ; pinnae 10-16-foliolate. 2. P. pubescens (E, F, G, H). 



1. Prosopis juliflora, DC. Mesquite. Honey Locust. 



Leaves with 2 or rarely 4 pinnae and slender terete petioles abruptly enlarged 

 and glandular at the base; stipules linear, acute, membranaceous, deciduous. 

 Flowers appearing in successive crops from May to the middle of July, fragrant, 



about ^^2' long, on short pedicels, in slender cylindrical spikes l^'-4' long, on stout 

 peduncles ^'-|' in length; calyx glabrous or puberulous, about one fourth as long as 

 the narrowly oblong acute petals glabrous or puberulous on the outer surface and 

 covered on the inner surface toward the apex with hoary tomentum; stamens twice 

 as long as the corolla, the dark-colored connective of the anther-cells furnished at 

 the apex with a stalked gland; ovary short-stalked, clothed with silky hairs. Fruit 

 in drooping clusters, linear, at first flat, becoming subterete at maturity, constricted 



