Milkvine, MateleaAubl., is recognizable as being in the milkweed family due unique features of the flower structure. This was the very thing I noticed the first time I ever saw one. The same is true of the seed pods. Depending on the
species of Matelea the variation of the flower color can intergrade from maroon to yellow/green while the seed pods can be eithersmooth or spiny. All of the Matelea I have seen around here has been growing in areas with limestone bedrock. The species that are reported in or near Alabama include: the relatively rare Alabama milkvine, M.alabamensis (Vail) Woodson, Baldwin's milkvine, M.baldwyniana (Sweet) Woodson, maroon Carolina milkvine, M.carolinensis (Jacq.) Woodson, which is likely the one on the right, oldfield milkvine,M.decipiens (Alexander) Woodson, yellow Carolina milkvine, M.flavidula (Chapm.) Woodson, angularfruit milkvine,M.gonocarpos (Walter) Shinners, which is likely the one on the left, climbing milkvine, M.obliqua (Jacq.) Woodson, and Florida milkvine, M.floridana (Vail) Woodson, which is indigenous to Florida.