A tree, 50°—60° high, with a short trunk 2°—2½° in diameter, usually dividing a few feet from the ground into stout spreading often contorted branches forming a wide irregular flat-topped head, and glabrous orange-brown branchlets becoming in their second year gray or reddish brown, marked by occasional large pale lenticels, and armed with usually flattened simple or short-branched straight or falcate sharp rigid spines 3′—5′ long, about ½′ broad at the base, and dark red-brown and lustrous. Bark ⅛′—¼′ thick, smooth, dull gray or reddish brown, and divided by shallow fissures into small plate-like scales. Wood heavy, very hard and strong, coarse-grained, rich bright brown tinged with red, with thick light clear yellow sapwood of about 40 layers of annual growth.
Distribution. Eastern South Carolina to Florida, through the coast region of the Gulf states to the valley of the Brazos River, Texas, and northward through western Louisiana and southern Arkansas to northwestern Mississippi, middle Kentucky and Tennessee, the bottoms of the Mississippi at La Pointe, Saint Charles County, Missouri, western and southern Illinois and southwestern Indiana; rare east of the Mississippi River and only in deep river swamps; very abundant and of its largest size westward on rich bottom-lands; in Louisiana and Arkansas often occupying extensive tracts submerged during a considerable part of the year.
9. PARKINSONIA L.
Trees or shrubs, with smooth thin bark and terete branches often armed with simple or 3-forked spines. Leaves abruptly bipinnate, alternate or fascicled from earlier axils, short-petiolate, the rachis short and spinescent, with 2—4 secondary elongated rachises bearing numerous minute opposite entire leaflets without stipels; stipules short, persistent and spinescent, or caducous. Flowers perfect on thin elongated jointed pedicels from the axils of minute caducous bracts, in slender axillary solitary or fascicled racemes; calyx short-campanulate, 5-lobed, the lobes slightly imbricated or subvalvate in the bud, narrow, membranaceous, nearly equal, becoming reflexed, deciduous; petals bright yellow, unguiculate, much longer than the lobes of the calyx, spreading, the upper petal rather broader than the others and glandular at the base of the claw; stamens 10, inserted in 2 rows on the margin of the thin disk, free, slightly declinate, those of the outer row opposite the sepals and rather longer than the others; filaments villose below the middle, the upper filament enlarged at base and gibbous on the upper side; anthers uniform, versatile; ovary short-stipitate, pilose, contracted into a slender filiform incurved style infolded in the bud and tipped with a minute stigma; ovules numerous, suspended from the inner angle of the ovary. Legume linear, torulose, acuminate at the ends, 2-valved, the valves thin, convex by the growth of the seeds, contracted between and beyond them, longitudinally striate. Seeds oblong, suspended longitudinally on a slender funicle; hilum minute, near the apex; seed-coat thin, crustaceous, light brown; embryo inclosed on the sides only by thick layers of horny albumen; cotyledons oval, flat, slightly fleshy, the radicle very short and straight.
Parkinsonia, with four species, is confined to the warm parts of America and to southern Africa. Two species occur within the limits of the United States.
The genus is named for John Parkinson (1567—1650), an English botanical author, and herbalist to James I.
CONSPECTUS OF THE NORTH AMERICAN SPECIES.
Flowers in long slender racemes; petals imbricated in the bud; stamens shorter than the petals; legume 1—8-seeded, 12′—18′ long; leaves 7′—8′ long; rachis of the pinnæ flat, wing-margined, 50—60-foliolate; branches with spines.1. [P. aculeata] (G, H). Flowers in short racemes; petals valvate in the bud; stamens longer than the petals; legume 1—2-seeded; leaves about 1′ long; rachis of the pinnæ terete, 8—12-foliolate; branches without spines.2. [P. microphylla] (G, H).
1. [Parkinsonia aculeata] L. Retama. Horse Bean.
