Begonia melanobullata

Toad Wart Begonia, Black Bullate Begonia

Named for its most striking feature — melano meaning 'black' and bullata meaning 'blistered' — Begonia melanobullata is a rare rhizomatous begonia endemic to the limestone karst hills of Cao Bang province in northern Vietnam, where it clings to semi-shaded wet cliffs at 300–400 m elevation. Each wide, asymmetric leaf is studded with prominent dark maroon to near-black conical bullae, 2–8 mm high, each tipped with a velutinous hair — giving the foliage an almost armoured, tactile surface. It does best in the high humidity and indirect light of a closed terrarium, but it needs good airflow to stay healthy; standing water on the leaves can cause fungal rot. A slow-growing and increasingly collectible species, closely related to Begonia ferox.