Family Code: HYDRAN Genus Code: HYDRA Genus CN: hydrangea Genus Authority: L. Genus Summary: A genus of about 45 species, shrubs and lianas, of e. North America and e. Asia. Molecular analyses have long suggested that Hydrangea as usually interpreted is polyphyletic (Soltis, Xiang, & Hufford 1995; Samain, Wanke, & Goetghebeur 2010) and should be circumscribed more broadly to include other genera in tribe Hydrangeeae that are phylogenetically embedded (including, in our area, Decumaria); this approach has been further developed and formalized by De Smet et al. (2015), an approach followed here (generic and sectional circumscriptions follow De Smet et al. 2015). See Dirr (2004) and van Gelderen & van Gelderen (2004) for information on cultivated hydrangeas. Genus Identification: Identification notes: Hydrangea barbarais readily distinguished from the other opposite-leaved, woody vines in our flora (Gelsemium, Trachelospermum, Lonicera, Bignonia, Campsis, and Clematis) by its leaves (simple, ovate, and usually serrate) and climbing structures (adventitious roots). Genus References: Freeman in FNA (in prep.); McGregor in FNA (in prep.); Pilatowski (1982)=Z; McClintock (1957)=Y; Hufford in Kubitzki (2004). Last Updated: 2019-11-29 Publish: 1