91. Theligonum Linnaeus, Sp. Pl. 2: 993. 1753.
假繁缕属 jia fan lü shu
Authors: Jiarui Chen & Michele Funston
Cynocrambe Gagnebin.
Herbs, annual or perennial, monoecious. Stems somewhat succulent. Raphides present. Leaves petiolate, somewhat succulent, lower ones opposite, upper ones apparently alternate due to anisophylly, entire; stipules interpetiolar, membranous, united at base to petioles. Flowers unisexual, rarely bisexual, axillary in upper nodes, small 1-3 flowered cymes, bracts reduced. Staminate flowers sessile; calyx limb reduced; perianth (equivalent to corolla) deeply lobed, lobes 2-5, valvate, spreading or reflexed at anthesis, 3-5 parallel nerves; stamens (2-)6-30, sometimes united basally in groups, anthers linear, dorsifixed at anthesis, free slender filaments, pistillode reduced. Pistillate flowers subsessile; calyx limb reduced; perianth (equivalent to corolla) tubular, oblique, upper part an elongate constricted mouth, 2-4 denticulate-lobed; staminodes reduced; ovary 1-celled; style simple, exserted; ovule solitary, basal. Fruit a nutlike drupe, compressed; seed U-shaped; endosperm fleshy.
Four species: E Asia, Atlantic Ocean islands, Mediterranean region; three species (two endemic) in China.
Traditionally, Theligonaceae have been treated as a monogeneric family of controversial relationship: Rubiales (Cronquist), Myrtales (Engler), Caryophyllales (Dalla Torre & Harms). However, recent reliable molecular data place it within a highly derived group of Rubiaceae (along with Galium, Hedyotis, and Rubia; Pl. Syst. Evol. 225: 43-75. 2000).
