Nyctaginaceae -- the four-o’clock family (30+, 300; distribution: tropical and subtropical worldwide, a few temperate members)
Habit herbs, shrubs, trees; betalains present
Leaves mostly opposite, simple; entire, often slightly unequal in size, estipulate; herbage commonly sticky glandular
Inflorescences cymes, umbels, heads, panicles, racemes, sometimes involucrate
Special floral characters petals absent, showy fused petaloid calyx often constricted above ovary, if involucrate: bracts can be showy
Calyx 5 sepals, petaloid, connate
Corolla absent
Androecium 1-30 stamens, distinct or filaments basally connate, free or adnate to calyx tube
Gynoecium 1 carpel; superior; 1 locule with 1 basal ovule; 1 style
Fruit= achene, often surrounded by hardened base of the calyx tube
(Floral formula: Ca 5 Co 0 A 5 G 1 )