Upright Carrion flower is a native perennial forb with annual stems, that are moderately branched and reach from one to three feet. Tendrils are normally absent. Stems are smooth, have no prickles and have blade-less stem bracts below the leaves.

The leaves are alternate and located on the upper 1/2 to 2/3rds of the stem. They can number up to 20 but usually less than 10; they are widely oval in shape, with parallel veins, and with a rounded to shortly pointed tip. Bases are truncate to shallowly heart-shaped. Leaf margins are generally smooth. The undersides are with fine hair. Smilax leaves are unusual in that they lack an abscission layer to separate the leaf at the end of the season. Instead the upper portion of the leaf stalk (the petiole) softens and disintegrates, allowing the leaf to fall off leaving a short stub. The leaf stalk of S. ecirrhata is shorter than the leaf blade.

The inflorescence consists of one to three ball-like umbels that are about 1.5 inches wide that form at the end of a stalk that rises from small bracts on the lower stem. Each umbel can have up to 25 flowers. Plants of the Smilax genus are dioecious, that is, male and female flowers are separate and on separate plants.

Flowers: The 6-parted flowers are minute and have 6 greenish-yellow tepals, each 3.5 to 4.5 mm long. Male flowers (staminate) have 6 stamens whose filaments more or less the same length as the anthers. Female flowers (pistillate) have a pistil with a 3-parted recurved stigma (style may be absent) and may have 6 infertile stamens (staminodes). Each flower is on a short stalk. Flowers have a scent of death when open, hence the common name.

Fruit: In Autumn a round fruit cluster is formed of 3/8 inch diameter blue-black berries that each contain 2 to 4 seeds.

 

Habitat: The plant grows from a short, woody rhizomatous base. A plant of moist woods growing best in partial sun, but is adaptable to full sun to full shade.

Names: The genus Smilax, is from the Greek, meaning 'clasping' and was applied by the Greeks to the various Greenbriers (or Catbriers) to which type this plant belongs, although this species lacks the tendrils to clasp anything. The author name for the plant classification of 1890 - 'S.Watson' is for Sereno Watson (1826-1892), American Botanist, assistant to Asa Gray and later curator of the Gray Herbarium at Harvard.

Comparisons: In close resemblance to this species are the Greenbriers which are similar climbing vines of this genus and produce similar blue-black berries. Roundleaf Greenbrier, S. rotundifolia, has rounded leaves, and usually has stem prickles; Bristly Greenbrier, S. tamnoides, has leaves more oval and the stems usually have bristly hair but can be smooth and angled. In both Greenbriers, the flower umbel stalk is no longer than a leaf stalk. Comparison drawings are below the photos.

S. lasioneura, the Common Carrion Flower, has umbels rising from the leaf axils not from bracts lower on the stem, is a climbing vine with tendrils from the leaf axils and the leaves, with heart shaped bases, are evenly divided on the stem. Another look-a-like species found in Minnesota is S. illinoensis, the Illinois Carrion-flower, which is erect with a longer stem than S. ecirrhata, has a number of tendril and has leaves with rounded to truncate bases with leaf stalks always equal to or longer than the leaf blade. Like S. ecirrhata, it also has the umbels located below the leaves arising from bracts on the stem but they are more in number, have up to 50 flowers and are on long stalks.