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1. Cornus Linnaeus, Sp. Pl. 1: 117. 1753.
山茱萸属 shan zhu yu shu
Shrubs, trees, or herblike shrubs, precocious, coetaneous, or serotinous. Young shoots pubescent, rarely glabrous; trichomes curly or straight, raised or appressed. Stem sympodial, rarely monopodial. Winter buds terminal or axillary, mixed or separate, covered or exposed. Petiole slightly furrowed adaxially; leaf blade narrowly elliptic, elliptic, oblong, or ovate, glabrous to densely pubescent, lateral veins actinodromous, often raised abaxially. Inflorescence formed in previous or current year; bracts covering inflorescence or not. Sepals 4, fused; teeth absent, minute, or variously triangular. Petals 4, free, spreading, oblong to orbicular, valvate. Filaments filiform or awn-shaped, longer than style, longer or shorter than petals; anthers whitish or yellow, rarely blue, red, or purplish, ellipsoid to narrowly ellipsoid or oblong, 2-loculed. Ovary obovoid, crowned by a disk. Fruit globose, ovoid, oblong, or ellipsoid, crowned by persistent calyx, disk, and style; stones globose, ovoid, ellipsoid, oblong, sometimes asymmetric, surface smooth or ribbed, apex rarely pitted.
Geographical distribution is the same as that of the family.
The classification of Cornus has long been debated. The ranks and circumscriptions of subgroups vary considerably among taxonomists. The current treatment retains Cornus in the broad sense as defined by Linnaeus and represents a synthesis of Ferguson (J. Arnold Arbor. 47: 100–105. 1966), Murrell (Syst. Bot. 18: 469–495. 1993), and Xiang (Acta Phytotax. Sin. 25: 125–131. 1987). This treatment agrees with recent molecular phylogenetic analyses of Cornus. The genus can be conveniently divided into distinct groups, all of which at one time or another have been recognized at full generic level. The keys below take advantage of those groupings.
Cornus esquirolii H. Léveillé (Repert. Spec. Nov. Regni Veg. 13: 257. 1914) was identified as Adina racemosa (Siebold & Zuccarini) Miquel (Rubiaceae) by Lauener (Notes Roy. Bot. Gard. Edinburgh 32: 97. 1972).
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| 1 |
Herblike shrubs, perennial, rhizomatous; leaves appearing whorled at summit of stem; inflorescences
corymbose cymes, subtended by 4 white petaloid bracts. |
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6 Cornus subg. Arctocrania |
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Trees or shrubs; leaves opposite or alternate; inflorescences paniculate, corymbose, umbellate, or cymes, subtended by showy petaloid bracts or not. |
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(2) |
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| 2 (1) |
Inflorescence capitulate, subtended by 4 large showy petaloid bracts; fruit of each inflorescence fused,
forming a compound drupaceous berry. |
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5 Cornus subg. Syncarpea |
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Inflorescences umbellate or paniculate or corymbose cymes, bracts not showy; fruit of each inflorescence
separate, distinct. |
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(3) |
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| 3 (2) |
Inflorescences umbellate, precocious; bracts subtending inflorescence orbicular, 3–4 mm; fruit oblong, red or blackish red. |
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4 Cornus subg. Cornus |
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Inflorescences paniculate or corymbose cymes, coetaneous or serotinous; bracts along branches
minute, linear or branched; fruit globose or ovoid, rarely ellipsoid, white, blue, or black. |
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(4) |
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| 4 (3) |
Leaves alternate; apex of fruit stone conspicuously pitted. |
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2 Cornus subg. Mesomora |
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Leaves opposite, rarely subopposite; apex of fruit stone not pitted. |
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(5) |
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| 5 (4) |
Evergreen; leaves leathery; style cylindrical; stigma subcapitate or punctiform; locules of fruit stone (2 or)3 or 4; anthesis autumn and winter; bracts inserted at base of inflorescence branches, often persistent to anthesis. |
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1 Cornus subg. Yinquania |
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Deciduous, rarely evergreen; leaves papery or rarely leathery; style cylindrical or clavate; stigma capitate or disciform, rarely punctiform; locules of fruit stone 2; anthesis spring and early summer, rarely autumn; bracts inserted distal and adnate to inflorescence branches, early caducous. |
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3 Cornus subg. Kraniopsis |
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List of lower taxa
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