Poaceae

Perianth segments 0–3, usually 2; flowers grouped into a characteristic spikelet (Fig. 48) Poaceae
Spikelets unisexual, male and female markedly different and in different inflorescences; plants monoecious or dioecious
Spikelets bisexual (rarely unisexual, and if so, the spikelets similar and in the same inflorescence)