Eupatorium rotundifolium
Distinguishing Features: leaves are ovate; stem and leaves are pubescent .
Habitat: open areas, old fields and waste places.
Geographic Distribution : diploid phase is restricted to coastal plain in northern Florida; apomictic polyploids are widespread in eastern U.S.
Similar Species: Eupatorium pilosum (treated as a variety of E. rotundifolium in many floras) has leaves that are somewhat more lanceolate, and the major branches of its inflorescence are often alternate rather than opposite; E. rotundifolium hybridizes with several other species, and the hybrids can be difficult to distinguish without molecular data.
Molecular Data : samples of E. rotundifolium (DNA #s ) differ in the ITS sequence from all other species by a minimum of 11 bp changes.
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