Smilax rotundifolia

Native

Woodland openings, thickets, roadsides.

May to June

Greenish-yellow

Up to 20′

This is a climbing, perennial, woody vine that rises on a single or multiple stems from a linear rhizome.

The stems are slender, green, woody, hairless, branching, and up to 20′ long. They are usually 4-angled, sometimes round. They are armed with stout, flattened, up to ½″ long prickles. The prickles are green with a black tip.

The leaves are alternate and deciduous. They are evenly distributed along the vine. They are on 3 ⁄16″ to ⅝″ long leaf stalks. The leaf stalks are shorter than the leaf blades. There is a pair of up tendrils at the base of many of the leaf stalks. The leaf blades are broadly egg-shaped to nearly circular, 1½″ to 6¾″ long, and 1½″ to 6¼″ wide. They are heart-shaped to rounded at the base and rounded at the tip with a short, sharp, abrupt point at the tip. The upper surface is bright green, shiny, and hairless. The lower surface is the same color as the upper surface, hairless, and sometimes shiny. The lower surface is not covered with a whitish, waxy bloom (glaucous). There are 3, 5, or 7 conspicuous main veins that arch from the base of the leaf blade and converge toward the tip. The main veins are impressed on the upper surface, raised on the lower surface. The margin is not thickened, lobed, or toothed, but may have a few scattered, minute, tooth-like projections.

The inflorescence is an globe-shaped, 1½″ in diameter, umbrella-like cluster (umbel) of 5 to 12, sometimes more, flowers rising from the leaf axils. The umbel is on a stalk that is up to ⅝″ long, shorter to slightly longer than the subtending leaf stalk.

Male and female flowers are borne on separate plants. There are 3 greenish-yellow, strap-shaped petals and 3 similar sepals (6 tepals). The male flowers have 6 stamens with yellow anthers. They appear in late May to late June.

The fruit is a glaucous, bluish-black to black, globular berry, ¼″ to ⅜″ in diameter.

Bristly greenbrier (Smilax tamnoides) has flexible, needle-like prickles. The fruit is not glaucous.

Sources: 7.