51. Mitchella Linnaeus, Sp. Pl. 1: 111. 1753.
蔓虎刺属 man hu ci shu
Authors: Tao Chen & Charlotte M. Taylor
Chamaedaphne Mitchell; Perdicesca Provancher.
Herbs, perennial, unarmed, creeping, rooting at nodes. Raphides present. Leaves opposite, without domatia; stipules generally persistent, interpetiolar, triangular, entire to deeply 3(-5)-lobed, often glandular at apex. Inflorescences terminal or pseudoaxillary near stem apices, 2-flowered, pedunculate, ebracteate. Flowers sessile, bisexual, distylous, fused in pairs by their ovaries. Calyx with ovary portion of individual flowers subglobose, with structure formed by fused ovaries oblate to dicoccous, with limb of individual flowers (3 or)4-lobed. Corolla white, funnelform, pilose in throat and onto lobes; lobes (3 or)4, valvate in bud. Stamens (3 or)4, inserted in corolla throat, exserted in short-styled flowers, included in long-styled flowers; filaments stout; anthers basifixed. Ovary of individual flowers 4-celled, ovules 1 in each cell, axile; stigmas 4, linear, exserted in long-styled flowers, included in short-styled flowers. Fruit multiple, orange to red, drupaceous, subglobose to oblate, fleshy, with calyx limbs 2, persistent; pyrenes 8, 1-celled, each with 1 seed, angled, 3-ridged; seeds medium-sized, ellipsoid; endosperm corneous; embryo small; radicle hypogynous.
Two species: one in E Asia (China, Japan, Korea), the other in Central America (Guatemala) and E North America (Canada, Mexico, United States); one species in China.
Y. Z. Ruan (in FRPS 71(2): 159. 1999) gave the number of calyx lobes, corolla lobes, and stamens as 3 or 4; in general, the flowers of Mitchella are considered 4-merous, although throughout Rubiaceae occasional individual flowers vary from the "characteristic" in having fewer or more calyx lobes, corolla lobes, and infrequently also stamens.