[5] The sole species in the genus is Gynerium sagittatum, a tall grass that grows up to six metres (twenty feet) high.

The species is known as "cana-do-rio", "cana-flecha", "cana-frecha", "ubá" and "cana-brava" in Brazil, "caña brava" in Peru and Colombia, "chuchío" in eastern Bolivia, and "tañil" in Guatemala and other Spanish speaking countries.

The upper part, round and thin, stiff on the outside and soft on the inside, develops a large bloom at the top.

The bark zone, which is the main factor in the unusual height, functions as a water distribution system, transporting water from the underground roots to the superior part of the plant including the leaves.

Being one of the first plants to colonise open areas, G. sagittatum is an important pioneer species that reaches new sites via wind-distributed seeds.