合欢草属（学名：Desmanthus）是含羞草科下的一个属，为乔木、灌木或多年生草本植物。该属共有约30种，分布于美洲和马达加斯加。

Desmanthus is a genus of flowering plants in the subfamily Mimosoideae of the pea family, Fabaceae. The name is derived from the Greek words δεσμός (desmos), meaning "bundle", and ἄνθος (anthos), meaning "flower". It contains about 24 species of herbs and shrubs that are sometimes described as being suffruiticose and have bipinnate leaves. Desmanthus is closely related to Leucaena and in appearance is similar to Neptunia. Like Mimosa and Neptunia, Desmanthus species fold their leaves in the evening. They are native to Mexico and North, Central and South America. Members of the genus are commonly known as bundleflowers. Donkey beans is another common name and originated in Central America, where Desmanthus species are highly regarded as fodder for these domestic draught animals.