Shrubs, vines, or herbs; rhizomes tuberous or stoloniferous, woody; roots filiform. Stems erect, sprawling or, more often, climbing, simple or branching, unarmed or armed with prickles; woody or herbaceous. Leaves deciduous or evergreen, alternate; stipules present; tendrils often present (few or rudimentary in S. hugeri and S. ecirrhata, absent in S. biltmoreana), paired, originating from petioles; blade linear, oblong, ovate, or, sometimes, reduced to scales in herbaceous species, base sometimes lobed. Inflorescences umbellate, axillary to leaves or bracts, loose to dense, pedunculate. Flowers unisexual; tepals 6, greenish, yellow, or bronze, ovate to elliptic; staminate flowers sometimes with pistillode, stamens 6, anthers basifixed, dehiscence introrse; pistillate flowers with 6 staminodes, style short or absent, stigmas 3, recurved, ligulate. Berries black, blue, purple, red, or orange. x = 13–16.
Worldwide in the tropics and subtropics, with extensions into temperate areas.
Species ca. 350 (20 in the flora).
The North American herbaceous species of Smilax (numbers 2, 5, 8, 9, 10, 11, 12, 14, and 15 in this treatment) traditionally have been placed in sect. Nemexia (Rafinesque) A. de Candolle. J. K. Mangaly (1968) concluded that the correct name for this group at that rank is sect. Coprosmanthus (Torrey) Bentham. The remaining North American species, all more or less woody, belong to sect. Smilax. The relatively small number of species (20) present in the flora does not warrant the elaboration of an updated subgeneric classification, which should take into account all species of the genus on a worldwide basis.
The leaves of Smilax are very unusual. A. Arber (1918, 1920) believed that the “blade of Smilax is not equivalent to the lamina of a dicotyledon but is merely a ‘pseudolamina’ representing an expansion of the upper region of the petiole.” In this view, tendrils are also proliferations of the petiole and are not homologous to tendrils of dicotyledons. However, D. R. Kaplan (1973) remarked that unifacial monocotyledonous leaves never exhibit a lamina rudiment at the apex, and therefore there is no convincing argument that their apices are simply petiolar. He suggested that the terete leaf axis of monocotyledons is not merely an expanded petiole but is positionally equivalent to the lamina region of a dicotyledonous leaf. Smilax leaves lack an abscission layer, but the distal portion of the petiole undergoes a soft disintegration and the “blade” falls, leaving a rough end on the stub (W. C. Coker 1944).
Smilax has numerous uses. Sarsaparilla, a beverage and medicinal used against rheumatism, is obtained from the rhizomes of various species, mainly from Mexico and Central America. A jelly can be made from the rhizomes. The fleshy rhizomes of several vining species, most notably S. smallii, which have a texture of firm, crisp apples, were used by Native Americans and early settlers in the same manner as were potatoes, or else in making bread or mush. The young, succulent stems of several species are cooked and used as asparagus or the tender stems may be used in salads. Seeds were sometimes used as beads (“Indian coral”) and a brown dye can be made from the roots of various species. Woody rhizomes were reportedly used by Native Americans and settlers in making pipes. Some species have been used in Native American (D. E. Moerman 1986) and folk medicine. All species of Smilax are excellent wildlife food and are also browsed, or the rhizomes dug and eaten, by domestic stock.
|1||Stems annual, herbaceous, without prickles; ovules (1–)2 in each locule.||> 2|
|1||Stems perennial, woody, usually prickly (especially at base); ovule 1 per locule.||> 10|
|2||Plants usually less than 1 m, erect; tendrils few and short or absent; umbels few, mostly axillary to bract.||> 3|
|2||Plants greater than 1 m, climbing; tendrils numerous, long, functional; umbels numerous, axillary to leaf.||> 6|
|3||Leaf blades glabrous, glaucous abaxially.||Smilax biltmoreana|
|3||Leaf blades pubescent, not glaucous abaxially.||> 4|
|4||Leaf blades broadly ovate, base cordate, apex acuminate.||Smilax ecirrata|
|4||Leaf blades narrowly ovate or elliptic, base mostly rounded, apex broadly rounded, obtuse, or abruptly acute.||> 5|
|5||Leaves disposed distally, ± equal; blade oblong, oblong-ovate, or oval; tendrils mostly absent; petiole shorter than blade.||Smilax hugeri|
|5||Leaves evenly distributed, progressively smaller proximally; blade narrowly ovate; tendrils usually present, but few; petiole usually equaling or longer than blade.||Smilax illinoensis|
|6||Leaf blades pubescent abaxially, with transparent trichomes.||> 7|
|6||Leaf blades glabrous abaxially.||> 8|
|7||Leaf blades abaxially dark green, lustrous; petiole ± equaling blade.||Smilax pulverulenta|
|7||Leaf blades abaxially pale green, not lustrous; petiole shorter than blade.||Smilax lasioneura|
|8||Leaf blades never hastate; tepals 3.5–4.5 mm; anthers much shorter than filaments.||Smilax herbacea|
|8||Leaf blades sometimes hastate; tepals 1.5–2.5 mm; anthers ± equaling filaments.||> 9|
|9||Plants less than 2 m; leaf blades coriaceous; peduncles (often 3 per axil) shorter than to ca. 1.5 as long as subtending leaf; berry diameter equaling length of pedicel; e United States.||Smilax pseudochina|
|9||Plants 2–3 m; leaf blades membranous; solitary pistillate umbel with peduncle longer than subtending leaf, staminate with peduncle equaling subtending leaf; berry diameter much less than length of pedicel; nw California.||Smilax jamesii|
|10||Stems densely pubescent; leaf blades densely pubescent abaxially; fruit red, apex pointed.||Smilax pumila|
|10||Stems glabrous (except for prickles); leaf blades glabrous or minutely pubescent abaxially; fruit red, orange, black, or purple, globose, ovoid, or flattened.||> 11|
|11||Leaf blades abaxially silvery to grayish, glaucous.||Smilax glauca|
|11||Leaf blades abaxially green, not glaucous.||> 12|
|12||Peduncle 1.5 or more times as long as petiole of subtending leaf.||> 13|
|12||Peduncle less than 1.5 times as long as petiole of subtending leaf.||> 15|
|13||Leaf blade margins with thickened, cartilaginous band, often revolute and appearing as prominent vein parallel to margins, entire to remotely spinose-ciliate, frequently lobed at base; prickles rigid, broad-based; leaves drying to uniform tan.||Smilax bona-nox|
|13||Leaf blade margins thin, flat, without cartilaginous band, uniformly minutely serrulate in lower half or entire, never lobed; prickles flexible, bristlelike; leaves drying to dull ashy green.||> 14|
|14||Leaf blade margins minutely serrulate in basal half; e United States.||Smilax tamnoides|
|14||Leaf blade margins entire; California, Oregon.||Smilax californica|
|15||Leaf blade margins spinose-dentate, teeth firm, spiny, or margins sometimes entire with thick edges; s Florida including the Keys.||Smilax havanensis|
|15||Leaf blade margins entire to lobed basally, without teeth or thick edges; widely distributed.||> 16|
|16||Leaves deciduous or partially evergreen; blade ovate, ovate-oblong, narrowly ovate, suborbicular, or reniform, base rounded to cordate.||> 17|
|16||Leaves evergreen; blade oblong, oblong-lanceolate, oblong-linear, lance-ovate, or narrowly ovate, base cuneate to attenuate (sometimes rounded in S. laurifolia).||> 18|
|17||Fruit bright red to orange; perianth brownish yellow; leaf blades ovate-lanceolate to ovate-oblong; in mud or shallow water.||Smilax walteri|
|17||Fruit black to blue; perianth yellowish green to bronze; leaf blades usually ovate to broadly ovate; dry sites.||Smilax rotundifolia|
|18||Distal leaf blades usually less than 5 cm, base auriculate, pandurate, or rounded.||Smilax auriculata|
|18||Distal leaf blades (5–)7+ cm, base unlobed.||> 19|
|19||Leaf blades lanceolate-ovate to narrowly ovate, prominently reticulate, often variegated, 5-veined from base, apex gradually narrowed, acute, or acuminate.||Smilax smallii|
|19||Leaf blades linear, oblong, lance-oblong, or narrowly elliptic, sometimes broadly ovate, not prominently reticulate, 3-veined from base, apex abruptly narrowed to acute point or rounded.||Smilax laurifolia|