Two species of Acœlorraphe have been distinguished; they inhabit southern Florida, and one species occurs also in Cuba and on the Bahama Islands.
The generic name, from ἀ priv., Κοῖλος and ῥαφη, refers to the character of the seed.
CONSPECTUS OF THE NORTH AMERICAN SPECIES.
Petioles furnished with stout marginal teeth throughout their entire length; leaves green on both surfaces, their primary divisions extending to the middle, secondary divisions only from 3½′—9′ long; stems forming large thickets. 1. A. Wrightii (D). Petioles furnished with thinner teeth, usually unarmed toward the apex; leaves green or glaucescent on the lower surface, their primary divisions extending nearly to the base, secondary divisions often 10′ long or more; stems often prostrate. 2. A. arborescens (D).
Leaves 30′—36′ in diameter, thin, light green, divided only to the middle, the divisions of the primary lobes 3½′—9′ long; petioles thin, gradually tapering from the base, 40′—60′ in length, armed throughout with stout straight or incurved teeth. Flowers: spadix 4°—6° long; flowers ⅛′—⅙′ long, with a light chestnut-brown calyx and a pale yellow-green corolla. Fruit ¼′ in diameter.
A tree with numerous stems, in Florida sometimes 10 metres high, forming great thickets.
Distribution. Dade County, Florida, from the rear of Madeira Hummock to Cape Sable, in swamps of fresh or brackish water at some distance from the coast; also in Cuba and on the Bahamas.
Leaves about 2° in diameter, light yellow-green on the upper surface, blue-green or glaucescent on the lower surface, divided nearly to the base into numerous lobes slightly thickened at the pale yellow midribs and margins; petioles 18′—24′ long, armed, except toward the apex, with stout flattened curved orange-colored teeth. Flowers: spadix 3°—4° long, with a slender much-flattened stalk, panicled lower branches 18′—20′ in length, and 6—8 thick firm pale green conspicuously ribbed spathes dilated at apex into a narrow border; flowers with a light chestnut-brown calyx and a pale yellow-green corolla. Fruit globose, ⅓′ in diameter; seed somewhat flattened below, with a pale vertical mark on the lower side, and a hilum joined to the micropyle by a pale band.