知母（学名：Anemarrhena asphodeloides）是龙舌兰科植物（原分类为百合科）。其干燥根茎入药，称知母，拉丁名Rhizoma Anemarrhenae。

Anemarrhena asphodeloides is a plant species in family Asparagaceae, subfamily Agavoideae, native to China, Korea, and Mongolia. It is the only species in the genus, and some authors have placed it in its own family, Anemarrhenaceae.