Asimina is confined to eastern North America. Six species are distinguished; of these one is a small tree; the others are low shrubs of the south Atlantic and Gulf regions.
Asimina is from Asiminier, the old colonial name of the French in America for the Pawpaw.
1. [Asimina triloba] Dunal. Pawpaw.
Leaves obovate-lanceolate, sharp-pointed at apex, gradually and regularly narrowed to the base, when they unfold covered below with short rusty brown caducous tomentum and slightly pilose above, and at maturity light green on the upper surface, pale on the lower surface, 10′—12′ long, 4′—6′ wide, with a prominent midrib and primary veins. Flowers nearly 2′ across when fully grown, on stout club-shaped pedicels from axils of the leaves of the previous year, 1′—1½′ long and covered with long scattered rusty brown hairs; sepals ovate, acuminate, pale green, densely pubescent on the outer surface; petals green at first, covered with short appressed hairs, gradually turning brown and at maturity deep vinous red and conspicuously venulose, those of the outer row broadly ovate, rounded or pointed at apex, reflexed at maturity above the middle and 2 or 3 times longer than the sepals, those of the inner row pointed, erect, their base concave, glandular, nectariferous, marked by a broad band of a lighter color. Fruit attached obliquely to the enlarged torus, oblong, nearly cylindric, rounded or sometimes slightly pointed at the ends, more or less falcate, often irregular from the imperfect development of some of the seeds, 3′—5′ long, 1′—1½′ in diameter, greenish-yellow, becoming when fully ripe in September and October dark brown or almost black, with pale yellow or nearly white barely edible flesh on some plants and on others with orange-colored succulent flesh; seeds separating readily from the aril, 1′ long, ½′ broad, rounded at the ends.
A shrub or low tree, sometimes 35°—40° high, with a straight trunk rarely exceeding a foot in diameter, small spreading branches, and slender glabrous or rusty pubescent, light brown branchlets tinged with red and marked by longitudinal parallel or reticulate narrow shallow grooves. Winter-buds acuminate, flattened, ⅛′ long, and clothed with rusty brown hairs. Bark rarely more than ⅛′ thick, dark brown, marked by large ash-colored blotches, covered by small wart-like excrescences and divided by numerous shallow reticulate depressions. Wood light, soft and weak, coarse-grained, spongy, light yellow shaded with green, with thin darker colored sapwood of 12—20 layers of annual growth. The inner bark stripped from the branches in early spring is used by fishermen of western rivers for stringing fish. The sweet and luscious wholesome fruit is sold in large quantities in the cities and towns in those parts of the country where the tree grows naturally.
Distribution. Deep rich moist soil; western New Jersey and western New York (Greece, Monroe County) to the northern shores of Lake Ontario, westward to southern Michigan, southwestern Iowa, southeastern Nebraska, eastern Kansas and eastern Oklahoma, and southward to Western Florida (Taylor County), central Alabama, and through Mississippi and Louisiana to eastern Texas (near Marshall, Harrison County, and Dennison, Grayson County); comparatively rare in the region adjacent to the Atlantic seaboard; very common in the Mississippi valley, forming thick forest undergrowth on rich bottom-lands, or thickets many acres in extent.
Occasionally cultivated in the eastern states, and hardy as far north as eastern Massachusetts; interesting as the most northern representative of the Custard-apple family and its only species extending far beyond the tropics.
2. ANONA L.
Trees or shrubs, with glandular often reticulated bark, terete branchlets marked by conspicuous leaf-scars, and often pubescent during their first season. Leaves coriaceous, often glandular-punctate, persistent or tardily deciduous. Flowers nodding on bracted pedicels; calyx small, 3-lobed, green, deciduous; petals 6 in 2 series, valvate in the bud, hypogynous, sessile, ovate, concave, 3-angled at apex, thick and fleshy, white or yellow, the exterior alternate with the lobes of the calyx, those of the inner row often much smaller than those of the outer row; stamens club-shaped, densely packed on the receptacle; filaments shorter than the fleshy connective; anther-cells confluent; pistils sessile on the receptacle, free or united; ovary 1-celled; style sessile or slightly stipitate, oblong, stigmatic on the inner face; ovule 1, erect; raphe ventral. Fruit compound, many-celled, fleshy, ovoid or globose, many-seeded. Seeds ovoid to ellipsoidal; cotyledons appressed.