LEGUMINOS^E 591 



2' long, in clusters of 2 or 3 on short peduncles abruptly and conspicuously enlarged at the 

 apex; valves thin and papery, bronze-green when fully grown, becoming dark red-brown, 

 separating slowly from the margins; seeds oval or obovoid, dark brown, lustrous, \' long. 



A tree, 50-60 high, with a trunk 2-3 in diameter, stout spreading branches forming 

 a wide flat head, and glabrous or somewhat pilose conspicuously verrucose branchlets, 

 bright red-brown when they first appear, becoming pale or light reddish brow r n in their 

 second year. Bark of the trunk of young trees and of the branches smooth, light gray 

 tinged with pink, becoming on old trunks \'-\' thick, dark brown and separating into 

 large plate-like scales. Wood heavy, hard, not strong, tough, close-grained, rich dark 

 brown tinged with red, with nearly white sapwood I'-l^' thick, of 4 or 5 layers of annual 

 growth; in Florida occasionally used and valued for boat and shipbuilding. 



Distribution. Florida; shores of Bay Biscayne near Miami, and the Everglade Keys, 

 Dade County, common, and on Key Largo, Elliott's, Plantation, and Boca Chica Keys, 

 not common; on the Bahama Islands and in Cuba. 



3. ACACIA Adans. 



Trees or shrubs, with slender branches armed with spinescent stipules or infrastipular 

 spines. Leaves alternate on young branchlets and fascicled in earlier axils, bipinnate, 

 with usually small leaflets, persistent. Flowers perfect or polygamous, small, in the axils 

 of minute linear bractlets more or less dilated and often peltate at apex, in globose heads 

 or cylindric spikes on axillary solitary or fascicled peduncles; calyx campanulate, 5 or 

 (>-toothed; petals as many as the divisions of the calyx, more or less united; stamens nu- 

 merous, usually more than 50, exserted, free or slightly and irregularly united at base, 

 inserted under or just above the base of the ovary; filaments filiform; anthers small, at- 

 tached on the back, versatile; ovary contracted into a long slender style terminating in 

 a minute stigma. Legume nearly cylindric or flat, indehiscent, continuous or divided 

 \vithin. Seeds transverse, compressed; seed-coat thick, crustaceous, marked on each face 

 of the seed by an oval depression or ring; radicle straight, included, or slightly exserted. 



Acacia with more than four hundred species is widely distributed through Australia, 

 where it is most largely represented, tropical and southern Africa, northern Africa, south- 

 western China, the warmer regions of southern Asia, the islands of the south Pacific, trop- 

 ical and temperate South America, the West Indies, Central America and Mexico to the 

 southwestern boundaries of the United States where ten or twelve species occur; of these 

 five are arborescent. Acacia is astringent, and many species yield valuable tan bark. 

 Gum arabic is produced by different Old World species; many of the species yield hard 

 heavy durable wood, and some of the Australian Acacias are large and valuable timber- 

 trees. Many species are cultivated for their graceful foliage and handsome fragrant 

 flowers. 



The generic name, from &Kaida, relates to the spines with which the branches are usually 

 armed. 



> 

 ( ONSPECTUS OF THE ARBORESCENT SPECIES OF THE UNITED STATES. 



Flowers in globose heads; corolla 5-Iobed; ovary sessile; stipules persistent, becoming 



spines. 



Legume cylindric, 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 short, often interrupted, spikes; legume flattened, pubescent, its sutures 



thickened; seeds in one rank. 3. A. Emoriana (E). 



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



stalked; stipules caducous; branchlets armed with infrastipular spines. 



