特徵描述
作者
YANG, YUEN-PO and LU, SHENG-YOU
型態特徵
Deciduous trees or shrubs; buds with scales. Leaves alternate, simple, serrate, rarely entire, penninerved, often oblique at base, petiolate; stipules paired, usually fugacious, caducous. Flowers unisexual or bisexual, solitary or in clustered cymes, racemes, panicles, or fascicles, apetalous; calyx 4 or 5-parted; stamens as many as and opposite calyxlobes, rarely twice as many; filaments straight; anthers extrorse, 2-celled, longitudinally dehiscent; ovary superior, sessile or stipitate; usually 1-celled; ovule 1, pendulous, anatropous or amphitropous; styles 2, simple or bifurcate. Fruit a samara, nut or drupe; seeds with scanty or no endosperm; embryo straight or curved.
屬
About 15 genera and more than 150 species, in tropical and temperate regions. Five genera with 15 species in Taiwan.
參考文獻
Ulmus 榆屬
作者
YANG, YUEN-PO and LU, SHENG-YOU
型態特徵
Deciduous shrubs or trees. Leaves serrate, penninerved; stipules lateral, free, scarious. Flowers bisexual, several in a cluster; calyx lobes 4-8, imbricate; stamens as many as and opposite the calyx lobes; ovary sessile or stipitate, compressed; style short, 2-fid or partite; ovule pendulous. Fruit flattened samara; seed ovate, flat.
