Cyperaceae
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 1–2 perfect flowers, other flowers male or sterile
Perianth scales or bristles present
Inflorescence paniculate, spicate or capitate
Bracts surrounding the head of spikelets with broad hyalo-membranous margins 1.5–3 mm wide Ptilothrix
Bracts of the inflorescence, which is not usually a head, with no hyalo-membranous margin or a very narrow one less than 1 mm wide