Flora of China
  FOC Vol.5 (2003)              | Family List  Ulmaceae  PDF     | Link Font:+ Big | - Small
   Ulmaceae  Mirbel
榆科   yu ke
Authors:Fu Liguo (傅立国 Fu Li-kuo) , Xin Yiqun (辛益群) ; Alan Whittemore

Fu Liguo -- Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, China. Xin Yiqun -- Department of Biology, Shandong University, Jinan, Shandong 250100, China. Alan Whittemore -- U.S. National Arboretum, U.S. Department of Agriculture, 3501 New York Avenue, N.E., Washington, D.C. 20002, U.S.A.


Trees or shrubs, evergreen or deciduous. Winter buds with scales, rarely naked; axillary buds developed; terminal bud usually dying back early. Stipules usually membranous, caducous. Leaves simple, alternate or rarely opposite, usually distichous, petiolate; leaf blade pinnately veined, basally 3(or 5)-veined, margin entire or serrate. Inflorescences axillary. Flowers monochlamydeous, bisexual, or rarely unisexual or polygamous. Perianth lobes 4-9, imbricate or rarely valvate, persistent or caducous. Stamens usually equal in number to and opposite perianth lobes, opposite, basally adnate to tepals; filaments distinct; anthers 2-celled, longitudinally fissured. Pistil 2-carpellate; ovary superior, 1(or 2)-loculed; ovule 1, suspended, anatropous; integuments 2. Style very short; stigmas 2, linear. Fruit samara, drupes, or winged nutlets, apically usually with persistent stigmas. Endosperm scanty or absent; embryo erect, curved, or involute; cotyledons flat, curved, or flexed. Seedling epigeous.

About 16 genera and ca. 230 species: widespread in temperate and tropical areas; eight genera (one endemic) and 46 species (23 endemic) in China.

Recent research strongly suggests that the subfamily Celtidoideae (Aphananthe, Celtis, Gironniera, Pteroceltis, and Trema) is not the closest relative of the subfamily Ulmoideae (Hemiptelea, Ulmus, and Zelkova). It would probably be more accurate to exclude Celtidoideae from Ulmaceae, and move it to Cannabaceae, rather than treating it as a separate family, Celtidaceae. More data are needed before a stable, new classification of the Urticales can be produced. Until these data are available, it is more practical to retain the traditional circumscription of Ulmaceae.

Most species of this family yield fine timber, the cortex is a good substitute for hemp, the fruit are edible, and the seed oil is used medicinally and industrially. Many species of Ulmaceae are cultivated, and it is not always certain whether specimens are from wild or cultivated plants.

Fu Likuo, Chen Chiajui & Tang Yancheng. 1998. Ulmaceae. In: Chun Woonyong & Huang Chengchiu, eds., Fl. Reipubl. Popularis Sin. 22: 334–413.

1Fruit dry, broadly winged at least on one side.(2)
+Fruit drupes (scarcely fleshy in Zelkova), not winged.(4)
2(1)Flowers unisexual; anthers apically pubescent; leaves 3-veined from base; secondary veins curving inward, not reaching margin.3  Pteroceltis    青檀属
+Flowers bisexual or polygamous; anthers apically glabrous; leaves pinnately veined; secondary veins straight, each ending in a marginal tooth.(3)
3(2)Fruit symmetric, winged on both sides; seed round; branchlets without spines.1  Ulmus    榆属
+Fruit asymmetric, winged only on one side; seed elongate and curved; branchlets with spines.2  Hemiptelea    刺榆属
4(1)Leaf blade 3(or 5)-veined from base.(5)
+Leaf blade pinnately veined.(7)
5(4)Lateral veins extending to margin, each ending in a tooth (Aphananthe aspera).6  Aphananthe    糙叶树属
+Lateral veins veins anastomosing before reaching margin.(6)
6(5)Flowers unisexual (polygamous in Trema cannabina), shortly pedicellate; fruit 1.5-4 mm in diam., with persistent tepals and stigmas, stalk short; leaf blade margin denticulate.7  Trema    山黄麻属
+Flowers polygamous, long pedicellate; fruit 5-15 mm in diam., without persistent tepals and stigmas, stalk long; leaf blade margin entire or serrate.8  Celtis    朴属
7(4)Flowers polygamous; leaf blade serrate to crenate; secondary veins extending to margin, each ending in a tooth.4  Zelkova    榉属
+Flowers unisexual; leaf blade entire, shallowly serrate, or denticulate; secondary veins anastomosing before reaching margin.(8)
8(7)Stipules usually basally connate, enclosing bud, leaving a single transverse scar that completely encircles stem at each node.5  Gironniera    白颜树属
+Stipules not connate, nor enclosing bud, leaving two small transverse scars one on each side of leaf base.(9)
9(8)Leaf blade narrowly ovate, ovate, or oblong-lanceolate, margin usually entire or occasionally inconspicuously serrate; drupe 13-20 mm (Aphananthe cuspidata).6  Aphananthe    糙叶树属
+Leaf blade elliptic-lanceolate to narrowly lanceolate, margin denticulate; drupe 1.5-2.5 mm (Trema levigata).7  Trema    山黄麻属
   Lower Taxon
  • Aphananthe  Planchon  糙叶树属
  • Celtis  Linnaeus  朴属
  • Gironniera  Gaudichaud-Beaupré  白颜树属
  • Hemiptelea  Planchon  刺榆属
  • Pteroceltis  Maximowicz  青檀属
  • Trema  Loureiro  山黄麻属
  • Ulmus  Linnaeus  榆属
  • Zelkova  Spach  榉属