Perennial, monoecious herbs, glabrous (or with hispid utricles). Leaves narrowly linear, flat or involute, more or less scabrid on margins and nerves; Inflorescence a single, terminal spikelet;
Andes present, Antarctic, Asia-Tropical: Philippines (Philippines present), Australasia: Tasmania (Tasmania present), E. Australia present, Falkland Is present, Indian Ocean present, Jamaica present, Mt Pulog present, New Zealand and neighbouring islands present, Northern America, Pacific: Hawaii present, S. America present, islands in the southern parts of the Atlantic present
A genus of probably Antarctic origin, with wide southern distribution; from the extreme south of S. America including the Falkland Is., along the Andes to Mexico and Jamaica; islands in the southern parts of the Atlantic and of the Indian Ocean; from Tasmania through E. Australia northwards to Malesia, Mt Pulog in the Philippines being the most northern extension; highly developed in New Zealand and neighbouring islands, from there one species extending to Hawaii. .
Subdivision of the genus. Kukenthal divided Uneinia into two subgenera, Uneinia ('Eu- Uneinia') and Pseudoearex, the latter containing only U. kingii Boott from Antarctic S. America, in which the rachilla is but shortly hooked. Subg. Uneinia is divided into two sections which are to some extent also geographically defined: sect. Uneinia, mainly Australian with few species in S. America, and sect. Platyan- dra which is exclusively American.