Herbs or shrubs, rarely trees, usually root hemiparasites, occasionally aerial hemiparasites (Dendrotrophe and Phacellaria); nodes not articulated, mostly glabrous, less often hairy, hairs simple. Leaves usually alternate (opposite in Buckleya), sometimes scale-like (absent in Phacellaria); stipules absent; petiole often indistinct; leaf blade simple, usually pinnately veined, sometimes palmately 3-9-veined (in Dendrotrophe), margin entire. Inflorescences mostly axillary, occasionally terminal (in Buckleya), cymose, umbellate, paniculate, racemelike, spicate, or clustered, sometimes 1-flowered; bracts scale-like, small, sometimes forming involucre, sometimes ± adnate to pedicel (in Thesium); bracteoles sometimes present, paired. Flowers bisexual or unisexual (plants usually dioecious, rarely monoecious), actinomorphic, 3-6(-8)-merous, very small; perianth lobes 3-6(-8), slightly fleshy. Male flowers: perianth lobes valvate or slightly imbricate in bud, incurved or patent when flowering, sparsely hairy or with tongue-shaped appendage at the insertion of the stamens. Disk epigynous or perigynous, sometimes absent, margin sinuate or lobed, sometimes distinct, glandular or scaly. Stamens as many as and opposite to perianth lobes, usually on the base of lobes; filaments filiform, short; anthers gynobasic or dorsifixed near base, 2-celled, parallel or divaricate, dehiscence usually longitudinal. Female and bisexual flowers: perianth tube usually longer than that of male. Ovary inferior or half-inferior, 1- or 5-12-loculed; ovules 1-3(-5), anatropous or hemitropous, integument absent. Style 1; stigma capitate, small, truncate or lobed. Fruit a drupe or a nut, exocarp usually fleshy, endocarp crustaceous or bony. Seed 1, without a differentiated testa; endosperm copious, usually white and partitioned, fleshy; embryo cylindric, straight, small, smooth, rugose, or many ridged. 2n = 5, 6, 7, 12, 13+.

Three species of sandalwood, Santalum album Linnaeus, S. myrtifolium Linnaeus, and S. papuanum Summerhayes, have been recorded as cultivated in China. Wu Zhengyi (editor’s note) adds that he collected a fruiting specimen of a Santalum in the coastal forests of Taiwan (at KUN).

About 36 genera and 500 species: widely distributed in tropical and temperate regions; seven genera and 33 species (13 endemic) in China.

(Authors: Xia Nianhe (夏念和) ; Michael G. Gilbert)