Carex uncinata is the most variable of the New Zealand species. It is chiefly distinguished by the number of female flowers which range from 35-180, and by the length of spikes (55-200 mm long).The glumes of this species are also characteristically deciduous. However, some forms are known where the glumes are persistent. The leaves of C. uncinata are usually dark green to yellow-green but in the southern part of its range dark red color forms are known.
