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CommentsThis small milkweed blooms later in the year than most milkweed species (Asclepias spp.), and its small umbels of flowers attract many kinds of insects, including butterflies. Whorled Milkweed (Asclepias verticillata) superficially resembles the common Field Horsetail (Equisetum arvense) because of its whorled linear leaves. It can be distinguished from this latter species by the milky latex of its foliage and the later development of its flowers and seedpods. Field Horsetail is a spore-bearing plant that lacks true flowers. Whorled Milkweed is readily distinguished from other milkweed species in Illinois by its more narrow leaves (only 2-3 mm. across). Narrow-leaved Milkweed (Asclepias stenophylla) is an exception, because its linear leaves are almost as narrow. However, this latter species has leaves that are alternate to nearly opposite along its stems, rather than whorled. So far, it has been found in only a few counties of western Illinois.