The genus consists of 25 species, three of which are of direct interest to Australia. The plants are large tussock-forming grasses growing to a height of about 2 m with stems to 6 m. The plants reproduce both by seed and vegetatively and are now spreading more rapidly on mainland Australia owing to the existence of bisexual plants that produce viable seeds. Previously most mainland plants were female clones which required pollination by a separate bisexual plant. Spread is mainly by man either knowingly or carelessly but the seed-bearing florets of the female plant are readily dispensed by wind. The plant is strongly invasive but seedlings are fragile and are especially palatable to grazing animals. Control is by herbicide or, preferably, by cutting and burning flower heads and grubbing out.