LEGIBIINOS^ 



541 



CONSPECTUS OF THE ARBORESCENT SPECIES OF THE UNITED STATES. 



Flowers in g-lobose heads j corolla 5-lobed; ovary sessile; stipules persistent, becoming 

 spines. 



Legume cylindrical, glabrous, its sutures conspicuously thickened and grooved ; seeds in 



2 ranks. 1. A. Farnesiana (E). 



Legume flattened, pubescent, its sutures not thickened, slightly grooved ; seeds in 



1 rank. 2. A. tortuosa (E). 



Flowers in elongated slender spikes ; corolla of 5 petals only slightly united at the base ; 



ovary stalked ; stipules caducous ; branchlets armed with inf rastipular spines. 



Legume 1' wide, straight or slightly contracted between the seeds, not becoming twisted 



and contorted at maturity ; seeds narrowly obovate or ovate. 3. A. "Wrightii (E). 



Legume ^'-f wide, often conspicuously contracted between the seeds, becoming twisted 



and contorted at maturity ; seeds nearly orbicular. 4. A. Greggii (E, G, H). 



1. Acacia Farnesiana, "Willd. Huisache. Cassie. 



Leaves 1'-^ long, with 2-8, usually 4 or 5, pairs of pinnse, generally somewhat 

 puberulous on the short petioles and rachises, in Texas mostly falling at the begin- 

 ning of winter; pinnae sessile or short-stalked, remote or close together, with 10-25 



fiq4^7 



pairs of linear acute leaflets tipped with minute points, miequal at the base, sessile 

 or short-petiolulate, glabrous or puberulous, bright green, ^-^ long. Flowers bright 

 yellow, very fragrant, ^^g' long, opening during the summer and autumn from the 

 axils of minute clavate pilose bractlets, in heads |' in diameter, on axillary solitary 

 slender puberulous peduncles, most often 2 or 3 together and I'-l^ long, with two mi- 

 nute dentate connate bracts forming an involucral cup immediately under the flower- 

 head; calyx about half as long as the petals and like them somewhat pilose on the 

 outer surface; stamens two or three times as long as the corolla; ovary short-stipi- 

 tate, covered with long pale hairs. Fruit oblong, cylindrical or spindle-shaped, thick, 

 turgid, straight or curved, slightly contracted between the seeds, short-stalked, nar- 

 rowed at the apex into a short thick point, 2'-3' long, |'-f ' broad, dark red-purple, 

 lustrous, and marked by broad light-colored bands along the thickened grooved 

 sutures, the outer coat of the walls thin and papery, inclosing a thick pithy pulp- 

 like substance surrounding the seeds, each in a separate thin-walled compartment; 



