; Sp. Pl. [Linnaeus] 1: 397 (1753) s. l.
Distribution: Himalayas, E-Asia, tropical Asia, North America to Chile, Hawaii (1). There is considerable disagreement re. taxonomy: De Smet al. (2015) include all genera in the group in a Hydrangea sensu latissimo, Ohba & Akiyama (2016) argue for separation of at least Hortensia, Heteromalla, Cornidia and Calyptranthe and a much narrower species concept.
= Adamia Wall.; Tent. Fl. Napal. 46. t. 36 (1824)
= Broussaisia Gaudich.; Voy. Uranie [Freycinet] 479, t. 69 (1826)
= Calyptranthe (Maxim.) H.Ohba & S.Akiyama; J. Jap. Bot. 91(6): 349 (2016), isonym
= Calyptranthe (Maxim.) Nakai; Bull. Natl. Sci. Mus. Tokyo 31: 52 (1952)
= Cardiandra Siebold & Zucc.; Fl. Jap. [Siebold] 119, t. 65, 66 (1839)
= Cianitis Reinw.; Syll. Pl. Nov. 68 (1825)
= Cornidia Ruiz & Pav.; Fl. Peruv. Prodr. 63. t. 35 (1794)
= Decumaria L.; Sp. Pl. [Linnaeus], ed. 2: Append. 1663 (1763)
= Deinanthe Maxim.; Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 7, 10: no. 16, 2 (1867)
= Dichroa Lour.; Fl. Cochinch. 301 (1790)
= Forsythia Walter; Fl. Carol. [Walter] 154 (1788) non Wahl (1805)
= Heteromalla (Rehder) H.Ohba & S.Akiyama; J. Jap. Bot. 91(6): 349 (2016)
= Hortensia Comm. ex Juss.; Gen. Pl. [Jussieu] 214 (1789)
= Macnemaraea Willemet; Ann. Bot. [Usteri] 18: 34 (1796)
= Pileostegia Hook.f. & Thomson; J. Proc. Linn. Soc., Bot. 2: 57, 76, t. 2 (1858)
= Platycrater Siebold & Zucc.; Fl. Jap. [Siebold] 1: 62, t. 27 (1835)
= Sarcostyles J.Presl ex DC.; Prodr. [A.P. de Candolle] 4: 15 (1830)
= Schizophragma Siebold & Zucc.; Fl. Jap. [Siebold] 58, t. 26 (1835)
= xDidrangea J.M.H.Shaw; Hanburyana 5: 47 (2011)
