Leptinella squalida subsp. mediana is endemic to the South and Stewart Islands. It is found from northwest Nelson and inland Marlborough to Fiordland, and on Stewart Island. It grows from coastal to alpine areas from sea-level to 2000 m a.s.l. It is widespread and abundant, and often found on river beds, cobble or sand beaches, in short tussock grassland, in alpine herbfields and sometimes in lowland wet depressions and ephemeral wetlands. On the eastern side of the South Island it is more common in wetter situations and is absent from drier areas to the south. It is a dioecious, widely creeping, fast-growing perennial herb forming dense monospecific turfs or intermingled with other turf species. It has rhizomes at or near soil surface, with dark green to red-green, flexible, hairy branches with hairy bronze-green foliage. It has green-yellow flowers from August to February.