蓪草（学名：Tetrapanax papyrifer），又名通脱木、木通树、通草（植物名实图考）及天麻子（云南土名）等，是常绿灌木，五加科蓪草属内的单属种植物。

木通树是小乔木，能生长到3-7米高，掌状大叶子7-12裂，下面被毛，长约40-60厘米，叶柄，叶片圆形，30-50厘米宽，巧妙的掌状波瓣有5-11个基本叶，每叶通常有辅小叶。茎含有大量白色髓。冬季开黄白色小花，花开在一个大伞状花序的顶峰，每花有4-5小白色花瓣，大型圆锥花序。通常在大型叶片顶端（表面上类似手掌冠）的无枝的茎上有着直径2厘米的莲叶丛状果实，为一个小球形核果，熟时黑色。它从地下的根系用芽广泛地传播。

Tetrapanax papyrifer (rice-paper plant, or 通草—tong cao) is an evergreen shrub in the family Araliaceae, the sole species in the genus Tetrapanax. The specific epithet is frequently misspelled as "papyriferum", "papyriferus", or "papyrifera". It is endemic to ******, but widely cultivated in East Asia and sometimes in other tropical regions as well. The species was once included in the genus Fatsia as Fatsia papyrifera.