黑莎草属（学名：Gahnia）是莎草科下的一个属，为多年生、粗壮草本植物。该属共有35种，主要分布于南半球。

Gahnia (sawsedge, saw-sedge) is a genus of sedges native to China, Southeast Asia, New Guinea, Australia, New Zealand and a number of Pacific Islands. The common name is due to the toothed margins. It often forms tussocks.