540 TREES OF NORTH AMERICA 



outer surface, especially above the middle, -fy long, and half as long as the 5-lobed 

 corolla with reflexed lobes ; stamens about 20, twice as long as the corolla, united for 

 one fourth of their length into a slender tube. Fruit stipitate, gradually narrowed 

 and acute at the ends, 4'-5' long, 1' broad, with a slender stem 1/-2' long, ripening in 

 the autumn and persistent on the branches until after the flowering period of the 

 following year, in clusters of 2-3 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 

 obovate, dark brown, lustrous, ' long. 



A tree, 40-50 high, with a trunk 2-3 in diameter, stout spreading branches 

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

 verrucose, bright red-brown when they first appear, becoming pale or light reddish 

 brown 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 1' 1^' 

 thick, of 4 or 5 layers of annual growth ; in Florida occasionally used and valued for 

 boat and shipbuilding. 



Distribution. Key Largo, Elliott's, Plantation, and Boca Chica keys, Florida; 

 not common; on the Bahama Islands. 



3. ACACIA, Adans. 



Trees or shrubs, with slender branches armed with spinescent stipules or infra- 

 stipular spines. Leaves alternate on young branches and fascicled in earlier axils, 

 bipinnate, with usually small leaflets, persistent. Flowers perfect or often polyga- 

 mous, small, in the axils of minute linear bractlets more or less dilated and often 

 peltate at the apex, in globose heads or cylindrical spikes, on axillary solitary or fasci- 

 cled peduncles; calyx campanulate, 5 or 6-toothed ; petals as many as the divisions of 

 the calyx, more or less united; stamens numerous, usually more than 50, exserted, 

 free or slightly and irregularly united at the base, inserted under or just above the 

 base of the ovary ; filaments filiform ; anthers small, attached on the back, versatile ; 

 ovary contracted into a long slender style terminating in a minute stigma. Legume 

 nearly cylindrical or flat, indehiscent, continuous or divided within. 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, 

 southwestern China, the warmer regions of southern Asia, the islands of the south 

 Pacific, tropical 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 four 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 

 species are large and valuable timber-trees. Many species are cultivated for their 

 graceful foliage and handsome fragrant flowers. 



The generic name, from OKOK/O, relates to the spines with which the branches are 

 usually armed. 



