Macroptilium lathyroides is a species of plant in the legume family (Fabaceae) commonly known as the phasey bean.

As it quickly spreads on disturbed soils, it is considered an environmental weed in some areas.

Seads are obliquely oblong, about 3 mm long, mottled light and dark grey-brown or black.

[3] Plants tend to form dense monocultures, but once established, they combine well with open grasses, particularly under fertile conditions.

Especially in shade, they readily twin with each other or other plants, reaching up to 1.5 m.[2][3] M. lathyroides is widely naturalized across the tropical areas of the world, cultivated for forage or as a green manure or cover crop in rotation.