Overview
The String of Nickels (Dischidia nummularia), also known as the button orchid or coin plant, is a delightful epiphytic succulent vine native to the warm, humid tropical rainforests of Southeast Asia and Australasia. Belonging to the milkweed and dogbane family (Apocynaceae), this charming climbing epiphyte is celebrated for its dense, cascading garlands of fleshy, circular leaves that look remarkably like strings of minted silver-green coins. Cascading from the trunks and boughs of ancient canopy trees, it embodies extraordinary botanical adaptations for moisture conservation, aerial climbing, and mutualistic insect ecology.
Biology and Physical Characteristics
Dischidia nummularia displays specialized vegetative adaptations for life suspended high above the jungle floor. Its slender, wire-like climbing stems produce pairs of opposite, coin-shaped (nummular) leaves that are thick, succulent, and flattened, measuring up to three-quarters of an inch in diameter. The leaves are covered in a pale, silvery-green glaucous powdery bloom that reflects excessive solar heat and retards water evaporation. Utilizing Crassulacean Acid Metabolism (CAM), the plant opens its stomata strictly at night to absorb carbon dioxide, dramatically reducing water loss during scorching equatorial afternoons. Along every node, adventitious aerial roots emerge to cling tenaciously to host tree bark, absorbing rainwater and dissolved mineral runoff.
Behavior and Ecology
In its native forest canopy, the String of Nickels is an active participant in complex myrmecophilous (ant-plant) mutualisms. The overlapping, coin-like succulent leaves press tightly against host tree trunks, creating sheltered, subterranean-like runways and chambers underneath. Arboreal ants establish colonies beneath these shingled leaves, defending the plant from herbivorous caterpillars while depositing nutrient-rich organic debris and frass, which the plant’s adventitious roots eagerly absorb for essential nitrogen and phosphorus. In season, the vine produces tiny, urn-shaped white or pale yellow flowers, followed by slender pods containing silky-tufted seeds that drift on canopy breezes.
Conservation and Human Impact
Evaluated as Least Concern, Dischidia nummularia remains widespread and common throughout tropical Asia’s lowland forests. While common in protected national parks, localized populations face pressures from extensive lowland deforestation, mangrove clearance, and timber logging. Widely cultivated globally as an exquisite, easy-care ornamental hanging houseplant, captive commercial propagation through stem cuttings has eliminated the need for wild harvesting, securing its wild forest populations.
Interesting Factoid
The thick, rounded leaves of this plant grow in dense, cascading rows that overlap so closely against tree bark that arboreal ants use them like natural roofing shingles to build weather-proof nesting tunnels.
Last updated: October 2026