A family of about 17 genera and 190-220 species, trees, shrubs, vines, and herbs, primarily north temperate. As here interpreted, the family Hydrangeaceae includes two well-marked groups, the Hydrangeae (including Decumaria and Hydrangea) and the Philadelpheae (including Deutzia and Philadelphus). This group has been shown by molecular research to be unrelated to the Saxifragaceae, and to have its closest affinities to the Loasaceae, Cornaceae, and Nyssaceae (Xiang et al. 2002; Soltis, Xiang, & Hufford 1995; Morgan & Soltis 1993).
Ref: Freeman (2016a) In Flora of North America Editorial Committee (2016); Hufford (2004) In Kubitzki et al. (2004); Morgan & Soltis (1993); Soltis, Xiang, & Hufford (1995); Spongberg (1972); Xiang et al. (2002). Show full citations.