Division 1. Monocotyledons.
Stems with woody fibres distributed irregularly through them, but without pith or annual layers of growth. Parts of the flower in 3’s; ovary superior; embryo with a single cotyledon. Leaves parallel-veined, alternate, long-persistent, without stipules.
III. PALMÆ.
Trees, growing by a single terminal bud, with stems covered with a thick rind, usually marked below by the ring-like scars of fallen leaf-stalks, and clothed above by their long-persistent sheaths; occasionally stemless. Leaves clustered at the top of the stem, plaited in the bud, fan-shaped or pinnate, their rachis sometimes reduced to a narrow border, long-stalked, with petioles dilated into clasping sheaths of tough fibres (vaginas); on fan-shaped leaves, furnished at the apex on the upper side with a thickened concave body (ligule). Flowers minute, perfect or unisexual, in the axils of small thin mostly deciduous bracts, in large compound clusters (spadix) surrounded by boat-shaped bracts (spathes); sepals and petals free or more or less united; stamens usually 6; anthers 2-celled, introrse, opening longitudinally; ovary 3-celled, with a single ovule in each cell; styles 1—3. Fruit a drupe or berry; embryo cylindric in a cavity of the hard albumen near the circumference of the seed. Of the 130 genera now usually recognized and chiefly inhabitants of the tropics, seven have arborescent representatives in the United States.
CONSPECTUS OF THE NORTH AMERICAN ARBORESCENT GENERA.
Leaves fan-shaped. Leaf-stalks unarmed. Calyx and corolla united into a short 6-lobed perianth. Fruit white, drupaceous; albumen even.1. [Thrinax.] Fruit black, baccate; albumen channeled.2. [Coccothrinax.] Calyx and corolla distinct; fruit baccate.3. [Sabal.] Leaf-stalks armed with marginal spines. Filaments slender, free; fruit baccate.4. [Washingtonia.] Filaments triangular, united into a cup adnate to the base of the corolla; fruit drupaceous.5. [Acœlorraphe.] Leaves pinnate. Flower-clusters produced on the stem below the leaves; fruit violet-blue.6. [Roystonea.] Flower-clusters produced from among the leaves; fruit bright orange-scarlet.7. [Pseudophœnix.]
1. THRINAX Sw.
Small unarmed trees, with stems covered with pale gray rind. Leaves orbicular, or truncate at the base, thick and firm, usually silvery white on the lower surface, divided to below the middle into narrow acuminate parted segments with thickened margins and midribs; rachis a narrow border, with thin usually undulate margins; ligule thick, concave, pointed, lined while young with hoary tomentum; petioles compressed, rounded above and below, thin and smooth on the margins, with large clasping bright mahogany-red sheaths of slender matted fibres covered with thick hoary tomentum. Spadix interfoliar, stalked, its primary branches short, alternate, flattened, incurved, with numerous slender rounded flower-bearing branchlets; spathes numerous, tubular, coriaceous, cleft and more or less tomentose at the apex. Flowers opening in May and June, and occasionally irregularly in the autumn, solitary, perfect; perianth 6-lobed; stamens inserted on the base of the perianth, with subulate filaments thickened and only slightly united at the base, or nearly triangular and united into a cup adnate to the perianth, and oblong anthers; ovary 1-celled, gradually narrowed into a stout columnar style crowned by a large funnel-formed flat or oblique stigma; ovule basilar, erect. Fruit a globose drupe with juicy bitter ivory-white flesh easily separable from the thin-shelled tawny brown nut. Seed free, erect, slightly flattened at the ends, with an oblong pale conspicuous subbasilar hilum, a short-branched raphe, a thin coat, and uniform albumen more or less deeply penetrated by a broad basal cavity; embryo lateral.
Thrinax is confined to the tropics of the New World and is distributed from southern Florida through the West Indies to the shores of Central America. Seven or eight species are now generally recognized.
The wood of the Florida species is light and soft, with numerous small fibro-vascular bundles, the exterior of the stem being much harder than the spongy interior. The stems are used for the piles of small wharves and turtle-crawls, and the leaves for thatch, and in making hats, baskets, and small ropes.