1096. Eupatorium japonicum Thunb.: Compositae
Authors: Hind Nicholas , Sasaki Yohko , Yasue Naoko 
Published: July 2024

Eupatorium japonicum Thunb. (Compositae: Eupatorieae: Eupatoriinae) is described and illustrated. The current synonymy is provided, together with type citations for each of the names and statements of the located type material, together with appropriate notes and comments on this material, including lectotypifications if present in the literature. A selection of verified illustrations of the species in the literature is provided. Statements of the species' distribution, habitat and ecological preferences, phenology, conservation status, and the etymology of both generic and specific epithets are given, along with an impressive array of vernacular names, reflecting its relatively wide distribution and long cultivation. Cultivation, propagation, and availability notes are provided. The probability of this plant having been ‘exported’ to China many centuries ago both for its scent and festival significance almost mirrors that of the Chrysanthemum, that came in the opposite direction a few centuries earlier. The author citation for this well‐known Japanese endemic is discussed, as is the long‐standing confusion between E. chinense L., E. japonicum and the separation of E. fortunei Turcz. in many references. Comments on Robert Fortune's Chinese collections relevant to the type material of Eupatorium fortunei are also provided. Included within the synonymy of E. fortunei is E. stoechadosmum Hance, published in a short paper, Manipulus …, in the Annales des Sciences Naturelles, the Monitum, is dated ‘7 kal. Februar. 1863’, suggesting publication of Cahier 4 post that date when it was published. Hance's novelties (some collected as late as November 1862), and those of Triana & Planchon in their Prodromus florae Novo‐Granatensis … (from Cahier 5) are listed in major databases as having been published in 1862; there is no other internal evidence in the relevant papers to suggest, or confirm, this is true. Any suggestion that Hance's Manipulis was published in early 1862 is similarly incorrect. Hance's plant supports other records, including the publication of E. fortunei Turcz., that E. japonicum had been long in cultivation in China, but never known to grow in the wild. Eupatorium japonicum, now with E. fortunei (fujibakama) in synonymy, is one of the seven plants, from the Festival of Seven Flowers or Herbs (nanakusa no sekku) that takes place in the autumn – the Autumn's Seven Flowers or Herbs (aki no nanakusa). The autumn tradition, dating back over a millennium, mirrors the spring festival (haru no nanakusa) – when a seven‐herb rice porridge is eaten – but in autumn the simplicity of the flowers is just for visual enjoyment, not eating. The herbal and medicinal uses of this species also have a long history, are wide‐ranging, and clearly have great potential in a number of fields, not least in preventing insect predation, as an insecticide, or as an ovicide, together with antifungal and antimicrobial activity, as well as showing good anti‐inflammatory and cytotoxic activity. The plant's Lavender‐like smell is akin to that produced in sakuramochi (Prunus speciosa (Koidz.) Ingram, of cherry blossom fame), but is based on coumarin and its derivatives, not linalool and related volatiles in Lavandula.