28 HOUGH'S AMERICAN WOODS. 



USES. No particular use is made of this wood, excepting it may 

 serve as fuel for the camp-fire of the traveler crossing the dreary 

 desert. 



MEDICINAL PROPERTIES are not known of this species. 



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, iritrorse, 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 

 d/ed^a), to sharpen, alluding to the spines with which many of the species are 

 armed. 



155. ACACIA MELANOXYLON, AITON. 



BLACK-WOOD. 

 Ger., Schwarzes IIolz; Fr.,, Boisnoir; Sp., Madera negra. 



SPECIFIC CHARACTERS : Leaves when they first appear bipinnate with many 

 pairs of small leaflets about one-quarter-inch long, but the pinnae soon fall away 

 and the remaining petioles develop into lanceolate-oblong somewhat falcate entire 

 obtuse prominently nerved phyllodia. Flowers yellow, in few heads arranged in a 

 raceme. Fruit a linear elongated curved pod, 2 in. long, in. broad, often curved 

 into a circle, flat with thickened margins and coriaceous glaucous valves; seeds 

 orbicular-oblong, black, with very long colored funicle more or less encircling 

 the seed in a double coil. 



(The specfic name, Melanoxylon, is from the Greek, yut'Ao:?, black, and vhov f 

 wood.) 



A large, handsome tree, of very rapid growth, and with full 

 rounded top of shining evergreen foliage. The bark of the large 

 trunks is of a reddish-brown color, with rather rough and firm longi- 

 tudinal ridges. 



HABITAT. The natural home of the Black- wood is in semi-tropical 

 Australia, but it has been introduced as an ornamental tree into Cali- 

 fornia, and there has become, in places, thoroughly naturalized; 

 hence is entitled to consideration as an American wood. 



