sour gum

1. The sweet gum, sour gum, and some Australian eucalyptus trees are gum trees.
   甜胶树、酸胶树和一些澳大利亚的尤加利树都是产树胶的树。

noun

1. columnar tree of eastern North America having horizontal limbs and small leaves that emerge late in spring and have brilliant color in early fall

   Synonym:    black gumpepperidgeNyssa sylvatica