Unarmed trees, with massive stems enlarged near the middle, and terminating in long slender bright green cylinders formed by the densely imbricated sheaths of the leaf-stalks. Leaves equally pinnate, with linear-lanceolate long-pointed unequally cleft plicately-folded pinnæ inserted obliquely on the upper side of the rachis, folded together at the base, with thin midribs and margins; rachis convex on the back, broad toward the base of the leaf and acute toward its apex; petioles semicylindric, gradually enlarged into thick elongated green sheaths. Spadix large, decompound, produced near the base of the green part of the stem, with long pendulous branches and 2 spathes, the outer semicylindric and as long as the spadix, the inner splitting ventrally and inclosing the branches of the spadix. Flowers monœcious, in a loose spiral, toward the base of the branch in 3-flowered clusters, with a central staminate and smaller lateral pistillate flowers, higher on the branch the staminate in 2-flowered clusters; calyx of the staminate flower of minute broadly ovate obtuse scarious sepals imbricated in the bud, much shorter than the corolla; petals nearly equal, valvate in the bud, ovate or obovate, acute, slightly united at the base, coriaceous; stamens 6, 9, or 12, with subulate filaments united below and adnate to the base of the corolla, and large ovate-sagittate anthers, the cells free below; ovary rudimentary, subglobose or 3-lobed; pistillate flowers much smaller, ovoid-conic; sepals obtuse; corolla erect, divided to the middle into acute erect lobes incurved at apex; staminodia 6, scale-like, united into a cup adnate to the corolla; ovary subglobose, obscurely 2 or 3-lobed, 2 or 3-celled, gibbous, the cells crowned with a 3-lobed stigma becoming subbasilar on the fruit; ovule ascending. Fruit a short-stalked drupe with thin crustaceous flesh. Seed oblong-reniform, marked by the conspicuous fibrous reticulate branches of the raphe radiating from the narrow basal hilum, and covered with a thin crustaceous coat; embryo minute, cylindric, lateral, in uniform albumen.
Roystonea is confined to the tropics of the New World, where two or three species occur.
The genus as here limited was named for General Roy Stone of the United States army.
1. [Roystonea regia] Cook. Royal Palm.
Oreodoxa regia H. B. K.
Leaves 10°—12° long, closely pinnate, the pinnæ, 2½°—3° long, 1½′ wide near the base of the leaf, and gradually decreasing in size toward its apex, deep green with slender conspicuous veins, and covered below with minute pale glandular dots; petioles almost terete, concave near the base, with thin edges separating irregularly into pale fibres, and enlarged into bright green cylindrical clasping bases 8° or 9° long and more or less covered with dark chaffy scales. Flowers: spadix about 2° long, with a nearly terete stem and slightly ridged primary and secondary branches compressed above, abruptly enlarged at the base, and simple slender flexuose long-pointed flower-bearing branchlets 3′—6′ long, pendant and closely pressed against the secondary branches; flowers opening in Florida in January and February, the staminate nearly ¼′ long and rather more than twice as long as the pistillate. Fruit oblong-obovoid, full and rounded at apex, narrowed at base, violet-blue, about ½′ long, with a thin outer coat and a light red-brown inner coat, loose and fibrous on the outer surface, and closely investing the thin light brown seed.
A tree, 80°—100° high, with a trunk rising from an abruptly enlarged base, gradually tapering from the middle to the ends and often 2° in diameter, covered with light gray rind tinged with orange color, marked with dark blotches and irregularly broken into minute plates, the green upper portion 8°—10° long, and a broad head of gracefully drooping leaves. Wood of the interior of the stem spongy, pale brown, much lighter than the hard exterior rim, containing numerous dark conspicuous fibro-vascular bundles. The outer portion of the stem is made into canes, and the trunks are sometimes used for wharf-piles and in construction.
Distribution. Florida, hummocks on Rogue River twenty miles east of Caximbas Bay, on some of the Everglades Keys, Long’s Key, and formerly on the shores of Bay Biscayne near the mouth of Little River; common in the West Indies and Central America.
Largely cultivated as an ornamental tree in tropical countries, and often planted to form avenues, for which its tall pale columnar stems and noble heads of graceful foliage make it valuable.