Of the one hundred and twenty-six genera of this family, which is chiefly confined to the tropics and is more abundant in the Old than in the New World, four have arborescent representatives in the United States.
CONSPECTUS OF THE ARBORESCENT GENERA OF THE UNITED STATES.
Fruit baccate. Fruit dark orange-color or yellow, with thin semitranslucent coriaceous flesh; ovules 1 in each cell of the ovary; leaflets subcoriaceous to coriaceous.1. [Sapindus.] Fruit purple, with thick juicy flesh; ovules 2 in each cell of the ovary; leaflets thin, persistent.2. [Exothea.] Fruit a drupe; leaves 3-foliolate, persistent.3. [Hypelate.] Fruit a 3-valved capsule; leaves 4 or 5, rarely 3-foliolate, deciduous.4. [Ungnadia.]
1. SAPINDUS L. Soapberry.
Trees or shrubs, with terete branches, without a terminal bud, marked by large obcordate leaf-scars showing the ends of 3 equidistant fibro-vascular bundles, small globose axillary buds often superposed in pairs, the upper bud the larger, and thick fleshy roots. Leaves equally or rarely unequally pinnate. Flowers regular, minute, polygamo-diœcious, on short pedicels from the axils of minute deciduous bracts, in ample axillary or terminal panicles; sepals 4 or 5, unequal, slightly united at base; petals 4 or 5, equal, alternate with the sepals, inserted under the thick edge of the annular fleshy entire crenately lobed disk, unguiculate, naked or furnished at the summit of the claw on the inside with a 2-cleft scale, deciduous; stamens usually 8 or 10, inserted on the disk immediately under the ovary, equal; filaments subulate or filiform, often pilose, exserted in the staminate, much shorter in the pistillate flower; anthers oblong, attached near the base; pistils 2 or 3, united; ovary sessile, entire or 2—4-lobed, 2—4-celled, narrowed into a short columnar style, rudimentary in the staminate flower; stigma 2—4-lobed, the lobes spreading; ovule solitary in each cell, ascending from below the inner angle of the cell; raphe ventral; micropyle inferior. Fruit baccate, coriaceous, 1—3-seeded, usually formed of 1 globose coriaceous carpel, with the rudiments of the others remaining at its base, or of 2 or sometimes 3 carpels more or less connate by their base and then 2—3-lobed. Seed solitary in each carpel, obovoid or globose; seed-coat bony, smooth, black or dark brown; tegmen membranaceous or fleshy; hilum oblong, surrounded by an ariloid tuft of long pale silky hairs; embryo incurved or straight; cotyledons thick and fleshy, incumbent; radicle very short, inferior, near the hilum.
Sapindus is widely distributed through the tropics, especially in Asia, occasionally extending into colder regions. About forty species have been distinguished; of these three are found within the territory of the United States.
Sapindus contains a detersive principle which causes the pulp of the fruit to lather in water, and makes it valuable as a substitute for soap. The bark, which is bitter and astringent, has been used as a tonic. The seeds of several of the species are strung for chaplets and bracelets and are used as buttons.
The generic name, from sapo and Indus, refers to the detersive properties and use of the first species known to Europeans, a native of the West Indies.
CONSPECTUS OF THE SPECIES OF THE UNITED STATES.
Leaves persistent. Rachis of the leaf interrupted-winged, with usually broad wings; leaflets 4—9, oblong-lanceolate and acute to elliptic-ovate or oblong, tomentulose below; petals without scales; fruit globose, orange-brown.1. [S. saponaria] (D). Rachis of the leaf without wings narrow-margined or marginless; leaflets 7—13, oblong-lanceolate, acuminate, often somewhat falcate, glabrous below; petals with scales; fruit somewhat oblong, dorsally keeled, yellow.2. [S. marginatus] (C). Leaves deciduous, their rachis without marginal borders; leaflets 8—18, lanceolate, mostly falcate, soft-pubescent or ultimately glabrous below; petals with scales; fruit globose, not keeled, turning black in drying.3. [S. Drummondii] (C, E).