Vines; rhizomes tuberous, or spinose, linear. Stems perennial, climbing, branching, green, often mottled, terete, to 5+ m, woody, glaucous, glabrous; prickles, when present, thin, 1-5 mm. Leaves deciduous to semi evergreen, ± evenly disposed; petiole 0.5-1.5 cm; blade green to glaucous-green, often mottled adaxially, silvery grayish abaxially, drying to brownish tan adaxially, broadly ovate, elliptic to reniform, with 3 (or 5) conspicuous veins, 4.5-11 × 2.5-6.6 cm, glabrous and glaucous abaxially, base truncate, subcordate, or attenuate, margins entire, apex rounded, tapering, or short-acuminate. Umbels few to many, axillary to leaves, 5-12+-flowered, open, umbellate to hemispherical; peduncle 2-5 cm. Flowers: perianth yellow to bronze; tepals 3-7 mm; anthers longer than filaments; ovule 1 per locule; pedicel 0.5-1 cm. Berries blue to black, subglobose, 8-10 mm, shiny black at maturity, glaucous. 2n = 28, 32. Flowering May--Jul. Dry to wet woods, thickets, hedge- rows, roadsides; 0--800 m; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Ky., La., Md., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va. Smilax glauca is easily recognized by its glaucous to whitened abaxial leaf surfaces, which, however, may be altered by heat in drying. It is reportedly the most weedy species of the genus. The plants tend to be evergreen in the more southern part of the distribution.
From Flora of Indiana (1940) by Charles C. Deam
Infrequent to common in the hilly counties of the southern part of the state and extending as far northward as Marion and Putnam Counties. It is found in open woodland and in fallow and abandoned fields. When it becomes established in cultivated ground, it is difficult to eradicate on account of its deep, tuberous rhizomes which, when broken, send up new stems.
Slender woody vine, seldom climbing very high; stems green and glaucous the first year, beset with stout prickles, the lower generally straight, the upper nodal and recurved; lvs often ±persistent, mostly ovate, often with cordate base, varying to subrotund or nearly triangular, 5-9 cm, half to three-fourths as wide, glaucous (and often long-papillate) beneath, at maturity subcoriaceous and shining above, thin and entire at the margin, 3- or 5(7)-nerved, the reticulate veins not prominently elevated; peduncles flattened, 1.5-3 times as long as the petioles; fr black, glaucous, 8-10 mm, mostly 2- or 3-seeded; 2n=32. Upland woods, roadsides, and thickets; Conn. to Fla., w. to O., s. Ill., se. Mo., Ark., and Tex. May, June.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.