This plant of semi shade smells like its name.
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| Illinois carrion flower in bloom in late May. |
The flowers smell, faintly, of rotting meat.
It's not overwhelming, but if you stick your nose close to the flowers and take a whiff, you'll pick it up: Definitely carcass-like.
The odor may make you recoil, but to insects it's alluring. Many kinds of flies are attracted not only by the smell but also by the pollen and nectar the flowers offer. They and an assortment of beetles and bees are the plant's primary pollinators (1, 2).
Pollination happens in spring, when nearly spherical flower clusters, called umbels, grow from the lower nodes. Each flower is light green and just a quarter of an inch (about 5 mm) across, with six tepals -- three sepals and three petals that look so much alike that they are indistinguishable.
Male (staminate) and female (pistillate) flowers are on separate plants, which means this species is dioecious (dy-EE-shus, literally meaning "two houses."). Male flowers have only stamens, six on each flower. They radiate outward like spokes on a bicycle wheel. Anthers, the pollen-producing organs on the tips of the stamens, are white to yellow.
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| Left: An umbel of male flowers, each with six stamens tipped with white anthers. Right: An umbel of female flowers with bulbous ovaries, short styles, and three lighter green, thread-like stigmas. This photo is (c) 2018 by Katy Chayka of Minnesota Wildflowers. |
Female flowers contains pistils, organs made of a somewhat bulbous ovary at the base, a neck called a style, and, at the tip, thread-like, pollen-collecting stigmas. Sterile stamens, called staminodes, may surround the pistil. They don't produce viable pollen, but they may serve some other function.
The smooth, round stems of carrion flower are more or less upright, unbranched and 2 to 3 feet long. Bract-like leaves grow at the base of the stem and broad, elliptical to egg-shaped leaves grow farther up. All leaves are alternate -- in other words, they are attached singly at the nodes, not in pairs or whorls.
Leaf blades are dark to medium green on the upper surface and lighter below from fine, white hairs -- in other words, the lower surface is pubescent. Several prominent, parallel veins run the length of the blades. Petioles (leaf stalks) of the largest leaves are at least as long as the leaf blades (1), but this characteristic is variable. The base of the blade is truncate (straight across) or rounded.
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| Leaf blade upper surface (left) and lower surface (right). The lower surface appears lighter green from the presence of short, fine, white hairs. |
Ends of stems bear tendrils.
After the pistillate flowers are pollinated, the ovaries grow into purple-black berries that are eaten by a variety of mammals and birds, such as raccoons, squirrels, cedar waxwings and cardinals. White-tailed deer will eat the young leaves (1).
According to MNTaxa, Illinois carrion flower is one of five Smilax species in Minnesota. All five are listed below, with synonyms in parentheses.
- S. ecirrhata, erect carrion flower
- S. herbacea, smooth carrion flower (S. herbacea var. herbacea)
- S. illinoensis, Illinois carrion flower
- S. lasioneura, common carrion flower (S. herbacea var. lasioneura)
- S. tamnoides, bristly greenbrier (S. hispida)
In contrast to MNTaxa, Minnesota Wildflowers reports only four species; noting that Smilax herbacea is not found in the state. All four species grow in the shade to part shade of deciduous woods, thickets, and similar habitats. The Upper Midwest range map for Illinois carrion flower is below, from the USDA Plants Database.
Several species look alike and can be hard to tell apart. The Minnesota Wildflowers website describes the characteristics that identify them, and this key from Michigan Flora also may be helpful. It includes S. hispida, a synonym for S. tamnoides, as well as S. rotundifolia, which has not been reported in Minnesota.
The Flora of North America also has a key to Smilax. It includes 20 species, including those found in Minnesota.
Cited References
2. Minnesota Pollination Guide
Additional References
Michigan Flora (key to Smilax species)
MNTaxa: The State of Minnesota Vascular Plant Checklist
Natural Resources Conservation Service. PLANTS Database. United States Department of Agriculture. Accessed May 30, 2026, from https://plants.usda.gov.
