The rice bean, which is known for its diverse distribution and range of adaptation from the humid subtropical to warm and cool temperate climate, is also found in the Himalayas, central China and extends to lower altitude limits in Malaysia. It is also grown in Myanmar, Malaysia, Fiji, Mauritius, Indonesia, Korea, Japan and in the Philippines. There are reports that the rice bean is also thriving in Honduras, Brazil and Mexico. The rice bean plant is erect to semi-erect or a vine.
Leaves are tri-foliate, leaflets being comparatively broader, hairy and usually trilobed.
Wild varieties of rice beans are perennial, very viny, and thin stemmed with a tuberous root system. Rice bean plant Rice bean flower Research on seedlings of different crops in India showed that rice bean has the highest growth efficiency and the lowest respiratory loss of seed reserves. The cultivars of rice beans are well adapted to practically the same areas as cowpeas. As a tropical crop, it is susceptible to frost, but tolerates high temperatures. As a short day legume, its flowering is only initiated when days are short.