Mucuna macrocarpa
The rusty-leaf mucuna is a large woody vine named for the distinctive color of its sap. When the vine is wounded, the exuded sap oxidizes and turns a deep reddish-brown-resembling blood-hence its Chinese name, which translates to “blood vine.” The plant exhibits a remarkable trait known as cauliflory, where flowers bloom directly on the mature trunk or thick branches. The flowering season occurs around early April, producing hanging clusters of purple-red blossoms. At first, the buds are enclosed by green sepals, and as they open, the vibrant petals emerge, forming pendulous inflorescences that display alternating hues of green and purple. The bell-shaped flowers create a vivid contrast of color, presenting a striking spectacle when in full bloom.
The rusty-leaf mucuna is a vigorous climber, its strong stems twining around nearby trees or supports as it ascends toward the sunlight. The branches are thick, and the leaves are trifoliolate, giving the entire plant a lush and dense appearance.
This species is distributed across tropical and subtropical Asia-from India, Nepal, Myanmar, Thailand, and Vietnam to China, Taiwan, and the Ryukyu Islands, extending northward to Kyushu, Japan. It typically grows in evergreen broadleaved forests, thriving along moist forest edges and streamside clearings at low to mid elevations. In Taiwan, it prefers warm, humid environments with abundant sunlight.
At the National Museum of Natural Science, two rusty-leaf mucuna plants are cultivated in the Vines and Succulents Area in front of the Research and Education Center of the Botanical Garden.