640 TREES OF NORTH AMERICA 



entire or finely serrate, covered at first with short close pubescence, becoming glabrous 

 and rather coriaceous at maturity, dark green and lustrous above, pale below, 4'-6' long, 

 2^'-3' wide, with a prominent midrib and primary veins; turning clear yellow in the autumn 

 before falling; petioles stout, thickened at base, 2|'-3' in length. Flowers appearing in 

 early spring on slender pubescent pedicels I'-l^-' long, the pistillate and stamina te flowers 

 produced together, the staminate usually less numerous and falling soon after the open- 

 ing of the anther^cells; calyx and petals pubescent; ovary puberulous. Fruit with a thin 

 almost orbicular sometimes slightly obovate wing, nearly 1' across, on a long slender re- 

 flexed pedicel, in dense drooping clusters remaining on the branches through the winter; 

 seeds 5' long, dark red-brown. 



A round-headed tree, rarely 20-25 high, with a straight slender trunk 6'-8' in diameter, 

 small spreading or erect branches, and slender branchlets covered at first with short fine 

 pubescence, becoming glabrous, dark brown and lustrous, and marked by wart-like excres- 

 cences and by the conspicuous leaf-scars; more often a low spreading shrub. Winter-buds 

 depressed, nearly round, pale or almost white. Wood heavy, hard, close-grained, yellow- 

 brown, with thin hardly distinguishable sapwood of 6-8 layers of annual growth. The bitter 

 bark of the roots is sometimes used in the form of tinctures and fluid extracts as a tonic, and 

 the fruit is occasionally employed domestically as a substitute for hops in brewing beer. 



Distribution. Generally on rocky slopes near the borders of the forest, often in the 

 shade of other trees; Long Island, New York, Pennsylvania, and westward through south- 

 western Ontario (Point Pelee) and southern Michigan to southern Iowa, southeastern 

 Nebraska, and southward to Georgia, Alabama, eastern Louisiana and through Missouri 

 and Arkansas to southeastern Kansas, eastern Oklahoma and eastern Texas. A form 

 with leaflets soft-pubescent on the lower surface (var. mollis T. & G.) occurs in the south 

 Atlantic states from North Carolina to Florida. 



Often planted as an ornament of parks and gardens. 



4. AMYRIS L. 



Glabrous glandular-punctate trees or shrubs, with balsamic resinous juices. Leaves op- 

 posite or rarely opposite and alternate, 3-foliolate, without stipules, persistent; leaflets 

 opposite, petiolulate, entire or crenate. Flowers white, minute, on slender bibracteolate 

 pedicels, usually in 3-flowered corymbs in terminal or axillary branched panicles; calyx 

 4-toothed, persistent; petals 4, hypogynous, much larger than the calyx-lobes, spreading 

 at maturity; disk of the staminate flower inconspicuous, that of the pistillate and perfect 

 flowers thickened and pulvinate; stamens 8, hypogynous, opposite and alternate with the 

 petals; filaments filiform, exserted; anthers ovoid, attached on the back below the mid- 

 dle; ovary ellipsoid or ovoid, 1-celled, rudimentary in the staminate flower; style short, ter- 

 minal, or wanting; stigma capitate; ovules collateral, suspended near the apex of the ovary, 

 anatropous. Fruit a globose or ovoid aromatic drupe; stone 1-seeded by abortion, charta- 

 ceous. Seed pendulous, without albumen; seed-coat membranaceous; cotyledons plano- 

 convex, fleshy, 'glandular-punctate. 



Amyris is confined to tropical America and northern Mexico. Of the twelve or fourteen 

 species which have been distinguished two extend into the territory of the United States; 

 one of these is a small West Indian tree common on the shores of southern Florida, and 

 the other, Amyris parvifolia A. Gray, a Mexican shrub, grows in Texas near Corpus 

 Christi, Neuces County, and near the mouth of the Rio Grande. Amyris is fragrant and 

 yields a balsamic aromatic and stimulant resin, and heavy hard close-grained wood valu- 

 able as fuel and sometimes used in cabinet-making. 



The generic name, from ptppa, relates to the balsamic properties of the plants of this 

 genus. 



1. Amyris elemifera L. Torch Wood. 



Leaves 3-foliolate, with slender petioles l'-l|' long, and broad-ovate or rounded obtuse 

 acute or acuminate leaflets cuneate at base, or sometimes ovate-lanceolate or rhombic- 



