This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Unarmed trees, with large bipinnate leaves, widely spreading branches, and perfect or polygamous capitate pink or white flowers, the heads sometimes panicled. Calyx tubular to campanulate, 5-lobed. Corolla funnelform. Stamens numerous, longer than the corolla; filaments united near the base of the corolla. Pods linear, flat, 2-valved, the margins of the valves not separating from them. [In honor of Albizzi, an Italian naturalist.]
About 50 species, natives of warm and tropical regions of the Old World, the following typical.
A. julibrissin Durazz. Mag. Tosc. 34: 11. 1772.
A tree, up to 35° high, and trunk diameter of 1 1/2°, the bark thin and scaly, the slender twigs smooth, reddish-brown. Leaves 8'-16' long, with 8-16 pairs of pinnae; the rachis tipped by a spine; leaflets 25 to 35 pairs, oblong, inequilateral, acute, 5"-8" long, revolute-margined, dark green above, pale green and pubescent beneath; heads panicled, about 2' in diameter; flowers pink; stamens more than 1' long; ovary short-stalked; pod 4'-6' long, narrowed at both ends, papery; seeds oval, flat, 4"-5" long.
Virginia to Florida and Louisiana. Naturalized from southern Asia. April-July.
3. ÁCUAN Medic. Theod. Sp. 62. 1786.
[Desmanthus Willd. Sp. Pl. 4: 1044. 1806.] [Darlingtonia DC. Ann. Sci. Nat. 4: 97. 1825.]
Perennial herbs or shrubs, with bipinnate leaves, small stipules, and greenish or whitish small regular flowers in axillary peduncled heads or spikes. Flowers perfect, sessile, or the lowest sometimes staminate, neutral or apetalous. Calyx campanulate, its teeth short.
Petals valvate, distinct, or slightly united or coherent below: Stamens 10 or 5, distinct, mainly exserted; anthers all alike. Ovary nearly sessile; ovules 00. Pod linear, straight or curved, acute, glabrous, flat, several-seeded, 2-valved, the valves coriaceous or membranous.
About 10 species, natives of warm and tropical America, one of them widely distributed in tropical regions of the Old World. Type species: Mimosa virgata L.
Pods few, linear, erect, straight.
Pods numerous in globose heads, oblong, curved.
Desmanthus leptolobus T. & G. Fl. N. A. 1: 402. 1840. Acuan leptoloba Kuntze, Rev. Gen. Pl. 158. 1891.
Herbaceous, ascending, branched, stems rough-angled, 2°-3° long. Leaves short-petioled, bipinnate; pinnae 5-10 pairs, sessile; leaflets 10-24 pairs, sessile, linear-lanceolate, acute, inequilateral, rounded at the base, usually glabrous, 1V-2" long, i" wide or less; peduncles 6"-12" long, few-flowered; stamens (always?) 5; pods 3-8, narrowly linear, acuminate, nearly straight, glabrous, about 3 times the length of the peduncle, 6-8-seeded.
Mimosa illinoensis Michx. Fl. Bor. Am. 2: 254.
Bot. 4: 358. 1842. A. illinoensis Kuntze, Rev. Gen. Pl. 158. 1891.
Ascending or erect, glabrous or nearly so, stems angled, 1°-3° high. Foliage resembling that of the preceding species, but the pinnae and obtusish leaflets are sometimes more numerous; peduncles 1'-2' long; pods numerous, densely capitate, oblong or lanceolate, strongly curved, 8"-12" long, acute, slightly impressed between the 2-5 seeds.