206. ACACIA DECURRENS GREEN WATTLE, BLACK WATTLE. 25 



PHYSICAL PROPERTIES. Wood heavy, hard, rather close-grained 

 with very fine medullary rays and not very strong. It is of a rich, 

 pinkish-brown color, streaked with darker and with a clear, light 

 greenish-yellow sap wood. Specific Gravity > 0.7609; Percentage of 

 Ash, 0.95; Relative Approximate Fuel Value, 0.7537; Coefficient of 

 Elasticity, 82424; Modulus of Rupture, 894; Resistance to Longi- 

 tudinal Pressure, 671; Resistance to Indentation, 329; Weight of a 

 Cubic Foot in Pounds, 47.42. 



USES. The wood is used to some extent in making rural fences 

 an J is excellent for fuel. The pods, owing to their sweetness and 

 nutritive value, serve as fodder and food for the Indians, though not 

 as valuable as the larger pods of the Prosopis juliflora. 



GENUS ACACIA, NECKER. 



Leaves variable, in the native American species bipinnate with usually small 

 leaflets in many pairs, but in many of the exotic species the leaflets fall away 

 and the petioles expand, becoming phyllodia ; stipules spinescent or inconspicu- 

 ous. Flowers perfect or polygamous, small, generally yellowish or greenish-white 

 in pedunculate globose or cylindrical spikes, each flower in the axil of a minute 

 linear or spatulate bractlet ; calyx campanulate, 4-5-toothed or sometimes divided 

 into distinct sepals, or reduced to hairs, valvate in aestivation ; petals of the same 

 number as the lobes of the calyx, generally more or less united below or rarely 

 wanting ; stamens numerous and indefinite, usually more than fifty, exserted, 

 free or slightly united at base, inserted beneath the ovary, filaments filiform, 

 anthers small, 2-celled, versatile, introrse, longitudinally dehiscent ; ovary sessile 

 or stipitate, two or many-ovuled, contracted into a long slender style with 

 minute terminal stigma ; ovules anatropous, suspended in two ranks from the 

 inner angle of the ovary. Fruit a legume, dehiscent by two valves or indehiscent, 

 continuous within or variously divided, very rarely separating into one-seeded 

 joints, the seeds usually ovate, compressed, without albumen and with thick 

 crustaceous testa. 



Genus composed of over 400 species of trees, shrubs and a few herbs of warmer 

 climates, and especially of Australia. About a dozen species are found native in 

 southwestern United States. The name is thought to be derived from the Greek 

 ciKdo>, to sharpen, alluding to the spines with which many of the species are 

 armed. 



206. ACACIA DECURRENS, WILLD. 

 GREEN WATTLE, BLACK WATTLE. 



Ger., Grune Acacie ; Fr., Acacia vert / Sp., Acacia verda. 



SPECIFIC CHARACTERS: Leaves all bipinnate, of 8-15 pairs of pinnae, with 

 numerous narrow rather distant leaflets, 1-4 lines in length ; branchlets glabrous 

 (or at first slightly pubescent) with prominent angles decurrent from the petioles. 

 Flowers (March to May) whitish yellow, iri terminal axillary panicled globular 

 heads. Fruit pods 3 or 4 in. long, flat, generally less than 4 lines wide and more 

 or less constricted between the seeds ; seeds ovate. 



The specific name, decurrens. the Latin for running down, is descriptive of the 

 ridges continuing along the branchlet from base of leaf-stalk. 



A beautiful small tree with graceful feathery foliage of various 

 shades of green and symmetrical rounded top. The trunks seldom 

 exceed 15 to 18 in. (0.45 m.) in diameter, and are vested with a bark 



