Description from Flora of China
Trees or shrubs, rarely rhizomatous herbs, mostly deciduous, sometimes evergreen, hermaphroditic [dioecious in African species]. Old branches terete, pith white or brown, lenticels and leaf scars often conspicuous; young branches rounded or slightly 4-ridged; nodes slightly swollen. Leaves opposite, rarely alternate or whorled, estipulate, petiolate, rarely sessile; leaf blade simple, entire, pinnately veined, rarely parallel veined, often pubescent, sometimes papillate; trichomes often 2-armed, arms equal or unequal, appressed and T-shaped, or raised and V- or Y-shaped, or pseudofiliform. Inflorescences cymose, paniculate, corymbose, umbellate, or capitulate, terminal, rarely lateral; bracts minute, not petaloid, early caducous, or 4(–6) and usually showy. Flowers 4-merous. Calyx tubular, fused to ovary, minutely 4-dentate or truncate. Petals 4, free, creamy white or yellow, rarely dark reddish purple or partially dark reddish purple, valvate. Stamens 4, surrounding a fleshy floral disk, alternate petals. Anthers longitudinally dehiscent. Ovary inferior; carpels 2, rarely 3 or 4; locules 2, rarely 3 or 4; ovules pendulous, 1 per locule; style 1, columnar or clavate; stigma capitate, disciform, punctate, or truncate, sometimes slightly 2-lobed. Fruit a drupaceous berry, white, blue, red, or black, berries distinct or fused into a fleshy syncarpous compound fruit; stone of fruit bony, 1- or 2(–4)-chambered, seeds 1 or 2(–4); endosperm oily; cotyledons 2, leaflike.
The family is treated here in the strict sense, excluding Alangium (Alangiaceae), Aucuba (Aucubaceae), Davidia (Davidiaceae), Helwingia (Helwingiaceae), Mastixia (Mastixiaceae), Nyssa (Nyssaceae), and Toricellia (Toricelliaceae), all of which have sometimes been placed in the Cornaceae. The Cornaceae in the FRPS included Mastixia, Cornus sensu lato, Aucuba, Helwingia, and Toricellia. Given that the latter three genera are allied with higher asterids in broad phylogenetic analyses, they are, therefore, removed from the Cornaceae in this treatment. These genera are recognized in the present volume as three families following Takhtajan (Sist. Magnoliofit. 1987). Based on molecular data, Mastixia is a close relative, but not the sister of, Cornus. Its relationships to Cornus and close relatives remain unclear. Thus, we also treat Mastixia as a family separate from Cornaceae. Although molecular data have suggested that Alangium is a member of Cornaceae, the genus will be treated as a separate family in a different volume of the Flora of China. This treatment of Cornaceae therefore includes only Cornus sensu lato.
The circumscription of the Cornaceae and the relationships among the 17 genera often placed within it have been controversial. The family has been defined as consisting of a single genus, Cornus, or up to as many as 15 genera by various authors (e.g., Harms, Ber. Deutsch. Bot. Ges. 15: 19–29. 1898; Takhtajan, Sist. Magnoliofit. 1987; Cronquist, Integr. Syst. Classif. Fl. Pl. 1988; Angiosperm Phylogeny Group, Ann. Missouri Bot. Gard. 85: 531–553. 1998; see also Xiang et al., Ann. Missouri Bot. Gard. 80: 723–734. 1993; Xiang & Soltis in Boufford & Ohba, Sino-Jap. Fl. Charact. Diversif. 123. 1998). Recent phylogenetic analyses of the chloroplast gene rbcL sequences (Xiang et al., loc. cit. 1993; Xiang & Soltis, loc. cit. 1998; Xiang, Harvard Pap. Bot. 4: 527–542. 1999) suggested that nine genera (Aralidium, Aucuba, Corokia, Garrya, Griselinia, Helwingia, Kaliphora, Melanophylla, and Toricellia) were not closely related to Cornaceae. Evidence from other studies, including pollen morphology and wood anatomy (Li & Chao, Quart. J. Taiwan Mus. 7: 119–136. 1954; Ferguson & Hideux, Proc. IV Int. Palynol. Conf., Lucknow 1: 240. 1980; Noshiro & Baas, IAWA J. 19: 43–97. 1998; see also Eyde, Bot. Rev. 54: 233–351. 1988), support the removal of these genera from Cornaceae. Various phylogenetic analyses of the rbcL and other chloroplast gene sequences identified a strongly supported monophyletic Cornales consisting of Alangium, Camptotheca, Cornus, Curtisia, Davidia, Diplopanax, Hydrangeaceae, Hydrostachyaceae, Grubbiaceae, Loasaceae, Mastixia, and Nyssa (Chase et al., Ann. Missouri Bot. Gard. 80: 528–580. 1993; Xiang & Soltis, loc. cit. 1998; Xiang, loc. cit. 1999; Olmstead et al., Molec. Phylogen. Evol. 16: 96–112. 2000; Savolainen et al., Kew Bull. 55: 257–309. 2000; Savolainen et al., Syst. Biol. 49: 306–362. 2000; Soltis et al., Bot. J. Linn. Soc. 133: 381–461. 2000; Albach et al., Ann. Missouri Bot. Gard. 88: 163–210. 2001; Albach et al., Taxon 50: 781–805. 2001). Phylogenetic analyses of the rbcL and matK sequences for the Cornales suggested a Cornaceae consisting of Alangium and Cornus, a Grubbiaceae consisting of Curtisia and Grubbia (Xiang et al., Amer. J. Bot. 85: 285–297. 1998; Xiang, loc. cit. 1999; Xiang et al., Molec. Phylogen. Evol. 24: 35–57. 2002; Fan & Xiang, Amer. J. Bot. 90: 1357–1372. 2003). The Cornaceae of Eyde (loc. cit. 1988), consisting of Camptotheca, Cornus, Davidia, Diplopanax, Mastixia, and Nyssa, were not supported by molecular data.
The hard wood of several species of Cornus is used for making farming tools. The fruit of some species is used for food or as a source of industrial oil. Cornus mas Linnaeus is cultivated in China for medicinal uses. Many species are widely cultivated as ornamentals, e.g., C. alba, C. canadensis, C. controversa, C. florida Linnaeus, C. kousa, C. mas, C. nuttallii Audubon, and C. stolonifera Michaux.
One genus and ca. 55 species: widespread in N temperate regions, extending to tropical and boreal areas, one species in tropical Africa and one or two species in South America; 25 species (14 endemic) in China.
(Authors: Xiang Qiuyun (向秋云 Jenny Xiang) ; David E. Boufford)
Hu Wenkuang. 1990. Bothrocaryum, Swida, Cornus, Dendrobenthamia, and Chamaepericlymenum. In: Fang Wenpei & Hu Wenkuang, eds., Fl. Reipubl. Popularis Sin. 56: 38–108.