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DescriptionThis is a herbaceous vine about 2-6' long that is either unbranched or branched occasionally. It either sprawls across the ground or climbs adjacent vegetation. This vine is either a summer annual or perennial (there are differing descriptions in this regard). The stems are light green, glabrous, angular, and prickly along their angles. The prickles are retrorse (curve downward) and about 1 mm. in length. Alternate leaves occur at intervals along the stems. These leaves are 2½-6' long and 2-4' across; they are hastate to broadly hastate in shape and smooth along their margins. The basal lobes of these leaves are triangular-shaped and divergent. Leaf tips taper to an acute point, while leaf bases are indented. The upper leaf surfaces are medium green and glabrous to sparsely short-pubescent, while the lower leaf surfaces are light green and sparsely to moderately covered with short stellate hairs. Small retrorse prickles occur along the major veins on the leaf undersides. Petioles are ½-4' long (becoming shorter as they approach the terminal points of stems), light green, and plano-convex (flat or slightly concave along their upper sides, convex along their lower sides). There are also retrorse prickles along the lower sides of the petioles. At the bases of petioles, there are ochrea (membranous sheaths) up to ½' long that wrap around the stems. These ochrea have rings of retrorse prickles around their bases, and their upper margins are often ciliate. Both axillary and terminal inflorescences are produced on peduncles about 1-4' long. These inflorescences are variable, consisting of dense head-like racemes, interrupted racemes that are sparsely flowered, and/or sparsely branched panicles consisting of 2 or more racemes. Sometimes only a single flower is produced, rather than a raceme of flowers. Each flower is about ¼' (5-6 mm.) long, consisting of 4-5 tepals, an ovary with a pair of styles, and 6 stamens (less often 8 stamens). The tepals can be reddish white, pinkish white, greenish white, or white; they are broadly elliptic in shape. The peduncles are light green, glandular-hairy, and sometimes prickly below. The blooming period occurs from mid-summer into the fall, lasting about 1-3 months. Afterwards, the flowers are replaced by seeds that are 3.5-4.0 mm. long and a little less across at maturity; they are ovoid, slightly flattened, biconvex (rounded on both sides), dark brown, and shiny. This vine can spread vegetatively by forming rootlets when the nodes of stems touch moist ground.