1. PISTACIA L.
Balsamic trees or shrubs. Leaves 3-foliolate or equally or unequally pinnate, petiolate, deciduous or persistent. Flowers small, diœcious, subtended by a bract and 2 branchlets, short pedicellate in panicles or racemes; calyx 1 or 2-lobed or in the pistillate flower 3—5-lobed, or 0; petals 0, stamens 3—5, 0 in the pistillate flower; filaments short, their base connate with the disk; anthers large; ovary subglobose or short-ovoid, rudimentary or 0 in the staminate flower; style 3-lobed, shorter than the 3 obovate-oblong or oblong stigmas. Drupe ovoid, oblique, compressed; exocarpa thin; the stone bony, 1-seeded; seed compressed; cotyledons thick plano-convex.
Pistacia with eight or nine species is confined to the valley of the lower Rio Grande, southern Mexico; the Canary Islands, the countries adjacent to the Mediterranean, and northern and central China, with one species growing on the northern banks of the Rio Grande in Texas.
The Pistacio-nuts of commerce, the green or yellow seeds of P. vera L. are largely used in confectionery, and some of the species are valued for the decoration of parks and gardens.
Pistacia from πιστ and ἄκεομαι, in reference to the healing properties of its resinous exudations.
1. [Pistacia texana] Swing.
Leaves persistent or tardily deciduous, 9—19-foliolate, with a slightly winged rachis pubescent above and a flattened narrow-winged petiole ½′—¾′ in length; leaflets spatulate, rounded and often mucronate at apex, gradually narrowed below into a deltoid or subcuneiform base, entire, more or less curved and unequilateral, wine-red when they unfold, and at maturity thin, dark green and sparingly pubescent along the midrib above, pale and glabrous below, nearly sessile or the terminal leaflet raised on a short petiolule, 5/12′—¾′ long and about ¼′ wide, with a slender midrib often near one side of the leaflet and reticulate veinlets. Flowers small, without a calyx, appearing just before or with the new leaves, in simple nearly glabrous panicles, their bracts and bractlets ciliate on the margins and wine-red at apex; staminate flowers more crowded than the pistillate, in compact panicles ¾′—1½′ long; anthers reddish yellow or wine color; pistillate flowers in loose panicles 1½′—2½′ in length; ovary ovoid or subglobose, two of the three styles with 2-lobed stigmas, the third with a 3-lobed stigma. Fruit oval, dark reddish brown and slightly glaucescent, about ¼′ long and ⅙′ broad, usually striate.
A small tree, occasionally 30° high with a short trunk 15′—18′ in diameter, with stout erect and spreading branches forming a head sometimes 30°—35° across, and slender slightly pubescent reddish branchlets becoming grayish brown by the end of their first year; more often a large shrub with numerous stout stems.
Distribution. Texas, limestone cliffs and the rocky bottoms of cañons periodically swept by floods, and in deep narrow ravines, along the lower Pecos River and in the neighborhood of its mouth, Valverde County; and in northeastern Mexico.