椴树科 duan shu ke
Authors: Ya Tang, Michael G. Gilbert & Laurence J. Dorr
Trees, shrubs, or herbs. Leaves simple, alternate or rarely opposite, basally veined, entire or serrate, sometimes lobed; stipule, when present, caducous or persistent. Inflorescences cymose or cymose-paniculate. Flowers bisexual or unisexual (plants dioecious), actinomorphic. Bracts caducous or sometimes large and persistent. Sepals (4 or)5, free or sometimes basally connate, valvate. Petals as many as sepals, sometimes absent, free, usually glandular on adaxial surface. Androgynophore present or absent. Stamens numerous, rarely 5, free or connate into fascicles at base; anthers 2-loculed, dehiscence longitudinal or apical; petaloid staminodes alternating with petals or absent. Ovary superior, 2-6-loculed, sometimes more; ovules 1 to many per locule; placentation axile; style simple, sometimes free; stigma acute or peltate, usually lobed. Fruit usually a drupe, capsule, or schizocarp, sometimes a berry or samara, 2-10-loculed. Seeds without aril; endosperm copious; embryo erect; cotyledons flat.
About 52 genera and ca. 500 species: primarily in tropical and subtropical areas; 11 genera and 70 species (32 endemic) in China.
Molecular data have shown that the members of the Tiliaceae as here defined fall clearly into four clades that can either be treated as subfamilies within an enlarged Malvaceae or as families in their own right. In this view the Tiliaceae/Tilioideae is restricted to Tilia and Craigia, along with the Central American Mortoniodendron Standley & Steyermark; Colona, Corchorus, Grewia, Microcos, and Triumfetta are placed in the Sparrmanniaceae/Grewioideae; Berrya and Diplodiscus are placed in the Brownlowiaceae/Brownlowioideae; and Burretiodendron and Excentrodendron form a basal group of uncertain placement, possibly most closely allied to the Pentapetaceae/Dombeyoideae which includes mostly genera here placed in the Sterculiaceae.
Plagiopteron Griffith, included in the Tiliaceae in FRPS (49(1): 48-50. 1989), is now regarded as either a member of the Celastraceae or a separate family, Plagiopteraceae (see Fl. China 11).
Chang Hung-ta & Miau Ru-huai. 1989. Tiliaceae. In: Chang Hung-ta, ed., Fl. Reipubl. Popularis Sin. 49(1): 47-123.