1077. Eurybia spectabilis (Aiton) G.L. Nesom: Compositae

Abstract

The North American Prairie plant Eurybia spectabilis (Aiton) G.L. Nesom (Compositae: Astereae: Machaerantherinae), the showy aster is illustrated and described, along with indications of distribution, habitat and ecology, flowering time, etymology, conservation status and vernacular names. The genus Eurybia (Cass.) Gray is endemic to North America and contains 22 species; it was first proposed as a subgenus of Aster L.; here the correct authority for the genus, and the disposition of Cassini's taxa is discussed—all his taxa now belong in Olearia Moench. Continuing issues with the infrageneric classification of Eurybia are highlighted, the molecular analyses not evidently supporting morphological studies. Eurybia spectabilis belongs to Eurybia subgen. Eurybia sect. Calliastrum (Torr. & A. Gray) G.L. Nesom, of which it is the lectotype; it is an octoploid species. The authority of the generic name is discussed. A full synonymy of the species is provided, together with a full type citation and location of known types together with relevant commentary. Cultivation, including suggestions for contrasting planting, or sympathetic border plantings, propagation, pests and diseases and availability of the species are discussed and commented on, and selected illustrations are cited. Only one natural hybrid, Eurybia ×herveyi A. Gray, purportedly between Eyrybia spectabilis and E. macrophylla (L.) Cass., is known. Spot characters to separate Eurybia spectabilis from Symphyotrichum laeve (L.) Á. Löve & D. Löve in the North American Prairie plantings are provided.