合萌属（学名：Aeschynomene）是蝶形花科下的一个属，为草本或灌木植物。该属共有约250种，分布于热带和亚热带地区。

Aeschynomene is a genus of flowering plants in the family Fabaceae, and was recently assigned to the informal monophyletic Dalbergia clade of the Dalbergieae. They are known commonly as jointvetches. These legumes are most common in warm regions and many species are aquatic. The genus as currently circumscribed is paraphyletic and it has been suggested that the subgenus Ochopodium be elevated to a new genus within the Dalbergieae, though other changes will also be required to render the genus monophyletic.