Comprehensive DescriptionRead full entry
CommentsWith the exception of the weedy Ranunculus abortivus (Small-Flowered Buttercup), this is probably the most common buttercup (Ranunculus spp.) in Illinois. It is possible to confuse Swamp Buttercup with similar species, especially Ranunculus hispidus (Hispid Buttercup), Ranunculus carolinianus (Carolina Buttercup), and the introduced Ranunculus repens (Creeping Buttercup). Unlike Swamp Buttercup, the stems of Hispid Buttercup have abundant spreading hairs and they are usually more erect. Carolina Buttercup is supposed to have longer achenes (3.5–5.0 mm. in length) than the preceding two species, however its status as a separate species is debatable. Some authorities consider Swamp Buttercup and Carolina Buttercup to be different varieties of Ranunculus hispidus (Duncan & Duncan, 1999; Yatskievych, 2000), although Mohlenbrock (2002) doesn't. The leaves of Creeping Buttercup are less deeply cleft and they are often splotched with pale green or white patterns. In addition, its achenes are less flattened than those of Swamp Buttercup.