1082. Rudbeckia hirta L.

Abstract

Rudbeckia hirta L. (Compositae: Heliantheae: Rudbeckinae) is described and illustrated. Material in Wakehurst's North American Prairie planting would key out to the widespread Rudbeckia hirta L. var. pulcherrima Farw., in that it is a perennial, leafy in the upper half of the stem and with narrow-lanceolate leaves. The issue of the rank of the currently recognized infraspecific taxa is highlighted and the cluttering of the synonymy with the recognition of minor, often horticultural variants discussed. A commonly cultivated species, this is one of several late-season flowerers in the American Prairie at RBG, Kew at Wakehurst Place. Cultivars are commonly cultivated, offering a considerable colour variation in the ray limbs, but it appears that the true species is relatively uncommon, possibly having come in and gone out of fashion since it was first brought into cultivation. 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 wide distribution and long cultivation. Comments are provided on the nectar, or honey, guides seen (under UV light) in Rudbeckia hirta. The guides are due to the presence of flavonol glucosides, these present only in the upper surface of the ray limbs. Historical uses of the species are noted, and phytochemical analyses have provided evidence that the anti-inflammatory properties have a factual basis.