Leaf sheath closed or rarely open and then the perianth reduced to bristles or minute scales Cyperaceae
Flowers bisexual or unisexual but never enclosed in a utricle and never apparently separated into unisexual spikelets
Spikelets with more than 2 perfect flowers
Perianth scales often numerous but always with 2 lateral ones keeled or at least concave; usually a number of flat ones inside these lateral scales
Perianth scales very rarely more than 6 or absent; lateral scales not keeled and scarcely concave