Pinellia is a small genus of tuberous perennial herbs in the family Araceae, native to East Asia — primarily China, Korea, and Japan. The genus comprises around nine accepted species, all sharing the characteristic Araceae inflorescence structure: a hooded green spathe from which protrudes a long, tongue-like extension of the spadix, earning them the common name "green dragons."
Leaves are highly variable across species, ranging from simple, heart-shaped (cordate) blades to compound leaves divided into three or many leaflets. Pinellia is notable for its vigorous reproductive capacity: plants produce seed abundantly and many species also form bulbils along the leaf stalks or at the leaf blade base. This dual reproductive strategy has allowed certain species to spread aggressively beyond their native range — most prominently Pinellia ternata, which has naturalized as a weed in temperate parts of eastern North America.
The genus is best known to Western botanists and horticulturalists through P. ternata, the most widespread and medicinally significant species. In Traditional Chinese Medicine, the processed corm of P. ternata (known as Ban xia or Zhi ban xia) has been used for millennia as a key herb for resolving phlegm, arresting nausea and vomiting, and treating throat conditions including goiters. Because the raw corm contains calcium oxalate crystals and other irritants, it must be processed — typically soaked in water or prepared with ginger — before internal use. Unprocessed material is restricted to topical applications.
Distribution
Pinellia is native to East Asia, with its center of diversity in China and extending into Korea and Japan. Several species, particularly Pinellia ternata, have established naturalized populations outside this native range, becoming invasive weeds in temperate eastern North America.
Ecology
Most Pinellia species grow in moist, shaded or semi-shaded habitats across East Asia. The genus reproduces prolifically via seed and through bulbils formed on the leaves, which detach and give rise to new plants. This combination of seed and vegetative reproduction makes species like P. ternata persistent and difficult to eradicate once established in disturbed ground or cultivated areas.
Cultural Uses
The corm of Pinellia ternata — processed to neutralize its natural toxicity — is among the most widely used herbs in Traditional Chinese Medicine, where it is called Ban xia (半夏) or Zhi ban xia (制半夏). It is prescribed in small doses (typically 3–6 g) within compound formulas to dry and resolve phlegm from the lungs, stop nausea and vomiting, and address conditions such as goiters or scrofula. Dried corm slices are also used as a moxa base. The raw, unprocessed corm is irritant due to calcium oxalate content and is only applied externally; internal preparations must first be soaked in water or processed with ginger to remove these compounds.
Taxonomy Notes
Pinellia belongs to the subfamily Aroideae within the family Araceae (the arum family). GBIF recognizes 9 accepted species in the genus. The genus name honors Giovanni Vincenzo Pinelli (1535–1601), an Italian botanist and bibliophile from Naples. The genus was described by Tenore.
