General description:- Herbs, shrubs or woody climbers, often with swollen nodes.
Leaves:- simple, entire, exstipulate.
Flowers:- Solitary or in small, terminal umbels (rarely in whorls), subtended by bracts which often simulate a perianth. Perianth petaloid, tubular, with a short, 5-lobed limb; lower part of tube persistent and growing together (concrescent) with the fruit to form an achene-like anthocarp. Stamens usually 3-5. Ovary superior, 1-celled, containing a single ovule.
Fruit:- Achene-like anthocarp.
MIRABILIS
General description:- Perennial herbs with opposite leaves.
Flowers:- In axillary cymes, each flower surrounded by a tubular or narrowly bell-shaped (campanulate), calyx-like involucre of 5 bracts. Perianth funnel-shaped (infundibuliform), with a long tube, contracted above the ovary, and a spreading, pleated (plicate), slightly 5-lobed limb. Stamens 5. Anthocarp leathery (coriaceous).
Key features:-
1) Bracts conspicuous, united around the base of each flower or umbel to form a calyx-like involucre.
2) Flowers solitary or in umbels of 3-5.
3) Perianth c. 25 mm diam.
4) Involucre tubular, not accrescent, or membranous, subtending only 1 flower.