Smilax glauca is frequent in sandy open forests, savannas, and fields just south of us in the Toledo area of Ohio, and may occur along the south edge of the state. It is woody, and has the undersides of the leaves as well as the first year stems strongly glaucous.
1. Leaves glabrous beneath (sometimes roughened on main veins); stems woody and prickly or herbaceous and smooth.
2. Stems herbaceous throughout, without prickles; umbels with more than 20 flowers; fruiting peduncles flattened or terete; fruit glaucous; ultimate branchlets terete or many-ridged (not sharply 4-angled).
2. Stems woody and prickly, at least at base; umbels with fewer than 25 (usually fewer than 20) flowers; fruiting peduncles strongly flattened; fruit not glaucous, or if so, the branchlets strongly 4-angled.
3. Youngest branchlets strongly 4-angled; fruit glaucous; prickles broad and flattened at base, green with (usually) dark tip; fruiting peduncles less than twice as long as the subtending petioles.
3. Youngest branchlets terete or with more than 4 ridges; fruit dark when ripe, not glaucous; prickles slender, terete, dark (or when young, green) throughout; fruiting peduncles twice as long as the subtending petioles, or longer.
1. Leaves finely puberulent, at least on the veins, beneath; stems herbaceous, never prickly.
4. Stem of full-grown plants over 1 m long, the main stem or elongate branches climbing (or resting on other objects for support); plant almost always branched, with total of more than 25 leaves; tendrils conspicuously curled, present at most nodes, including those from which peduncles arise; peduncles longer than petioles (sometimes several times as long), all or most arising from axils of foliage leaves; flowers (at least on main stem) more than 25 in an umbel (but not all develop into fruit).
4. Stem under 1 m tall, stiffly erect much of its length; plant unbranched, with fewer than 25 leaves (in S. illinoensis rarely more); tendrils absent or at most poorly developed and limited to uppermost nodes (never at the lower nodes from which peduncles arise); peduncles longer or, more often, shorter than petioles, at least the lowest ones usually arising from scale-like bracts on the stem below the foliage leaves; flowers more or fewer than 25 in an umbel.
5. Pistillate (and usually also staminate) flowers fewer than 25 in an umbel; leaves fewer than 20 (usually 7–9) on a plant; stems under 50 cm tall; peduncles usually shorter than the petioles or slightly longer; tendrils completely absent (rarely on upper 2–3 nodes).
5. Pistillate and staminate flowers usually more than 25 in an umbel and plants with one or more other exceptions to the above (i.e., leaves more than 20, stems over 50 cm tall, peduncles more than 2 cm longer than petioles, tendrils present on several upper nodes).