榆树，乔本的一种，双子叶植物中属榆科，主要在北半球的温带地区生长。一般高约25米，树皮粗糙。具高度实用、药用及食用价值。

榆树的叶呈椭圆形或椭圆状波针形，叶长2-8厘米、宽1.5-2.5厘米，两面叶面无毛，或背面脉腋有毛。叶侧脉有9-16对，叶缘有单锯齿，很少有重锯齿。叶柄长约2-10毫米。

榆树在早春发叶前先开花，花呈簇状生成聚伞花序，花被钟形，开4-5花瓣，每朵花有雄蕊约4-5条。翅果近圆形或宽倒卵形，长约1.3-1.5厘米，果皮表面无毛，顶端凹缺。内藏种子，近翅果中部，很少接近凹缺处；果柄长约2毫米。

Elms are deciduous and semi-deciduous trees comprising the flowering plant genus Ulmus in the plant family Ulmaceae. The genus first appeared in the Miocene geological period about 20 million years ago, originating in what is now central Asia. These trees flourished and spread over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of North America and Eurasia, presently ranging southward across the Equator into Indonesia.