Summary Eupatorium hyssopifolium L. (Compositae: Eupatorieae: Eupatoriinae) is described and illustrated, and the species is provided with an expanded synonymy that includes type citations, known types, and supplementary comments. Notes are provided for the species' cultivation, propagation, likely pests and diseases, and availability. The species' long history of cultivation, from 1699, is noted, although it is apparently not now commercially available in the United Kingdom. Selected illustrations of the species are cited, and statements of the species' distribution, habitat and ecology, phenology, etymology, conservation status and vernacular names provided. Additional commentary is provided concerning the conservation status and varying taxonomic concepts, as well as the presence of hybrids, polyploidy and taxonomic concepts.
Hind et al. (Wed,) studied this question.