An anomalous genus, by several authors doubtfully referred to Sapindaceæ, but chiefly on account of its bitter properties now placed in Simaroubaceæ. It consists of three species; of these the widely distributed Alvaradoa amorphoides Liebmann, the type of the genus, occurs in southern Florida. The other species appear to be confined to the islands of Jamaica and Cuba.
1. [Alvaradoa amorphoides] Liebm.
Leaves 4′—12′ long, with 21—41 leaflets and slender petioles; leaflets oblong-obovate, obtuse or occasionally minutely mucronate at apex, gradually narrowed below into a short slender pubescent petiolule, slightly thickened and revolute on the margins, dark green above, pale pubescent below, ½′—¾′ long, about ¼′ wide, with a slender midrib and obscure primary veins. Flowers regular, minute, diœcious, on slender accrescent pubescent pedicels from the axils of ovate minute deciduous bracts, in many-flowered hoary-tomentose racemes 3′—4½′ long, the pistillate accrescent, becoming 4′—8′ in length; calyx campanulate, 5-parted, the lobes ovate, acute, hoary-tomentose on the outer surface; disk 5-lobed; staminate flowers appearing sessile in the bud; their pedicels only slightly accrescent; petals filiform; filaments slender, elongated, slightly villose toward the base, inserted between the lobes of the disk and alternate with the calyx-lobes; anthers introrse, 2-celled, united except at apex, opening longitudinally by marginal slits, their connective orbicular, conspicuous; pistillate flowers on short accrescent pedicels; petals 0 or very rarely present; stamens 0; ovary compressed, unequally 3-angled, villose-hirsute on the margins, 3-celled at base, with two small compressed empty cells, the third larger with two anatropous ovules; styles 2, subulate or recurved, often of unequal length, stigmatic above the middle. Fruit lanceolate, acuminate, narrowly 2-winged, ciliate on the margins with long spreading hairs, slightly tinged with red, ¾′ in length and about two-thirds as long as its slender hairy pedicel; seeds acute at ends, pale yellow, ¼′ long.
A slender tree, in Florida occasionally 30° high, with a trunk 6′—8′ in diameter, and slender branchlets hoary-pubescent during their first year becoming dull red-brown, glabrous and marked by numerous small pale lenticels and by the large obovate obcordate scars of fallen leaves showing the ends of three conspicuous equidistant fibro-vascular bundles; in Florida more often a shrub.
Distribution. Florida, Everglade Keys (Timbo Hummock near Gozman’s Homestead, Caldwell’s Hummock and Long Key), Dade County; in the Bahama Islands, and in Cuba, southern Mexico, Central America and Argentina.
XXVIII. BURSERACEÆ.
Trees or shrubs, with resinous bark and wood. Leaves alternate, pinnate, without stipules. Flowers perfect or polygamous, in clustered racemes or panicles; calyx 4—5-lobed, the lobes imbricated in the bud, persistent; petals 4—5, imbricated in the bud, distinct or slightly united, deciduous; stamens twice as many as the petals, inserted under the annular or cup-shaped disk; filaments distinct, subulate; anthers introrse, 2-celled, the cells opening longitudinally; pistil of 2—5 united carpels; ovary 2—5-celled; styles united; stigma 2—5-lobed; ovules 2 in each cell, pendulous, collateral, anatropous; micropyle superior; raphe ventral. Fruit drupaceous. Seeds without albumen; seed-coat membranaceous; embryo straight; cotyledons foliaceous; radicle short, superior.
Of the sixteen genera of this family, which is widely distributed through the tropics of the two hemispheres, one only, Bursera, occurs in the United States, reaching the shores of southern Florida with an arborescent species, and southern California and Arizona with another species.