General description:- Herbs or shrubs.

Stems:- Often climbing.

Leaves:- Alternate, exstipulate.

Flowers:- Actinomorphic, in terminal or axillary inflorescences, sometimes solitary. Sepals 5, usually free. Corolla funnel-shaped (infundibuliform), tubular or bell-shaped (campanulate), usually 5-lobed or -angled. Stamens 5, alternating with corolla-lobes. Ovary 1- to 4-celled (locular), superior; ovules 1 or 2 in each loculus; style terminal.

Fruit:- A capsule.

CALYSTEGIA

General description:- Perennial rhizomatous herbs.

Stem:- Procumbent or climbing. White latex present.

Leaves:- Petiolate, variously lobed at the base.

Flowers:- Solitary, axillary, with a pair of large and sometimes inflated bracteoles partly or entirely concealing the sepals. Corolla large, infundibuliform or tubiform, glabrous or  fringed with hairs (ciliate). Ovary glabrous, unilocular; ovules 4. Stigma bilobed; lobes swollen and elongate. Pollen grains with rounded pores all over the surface (pantoporate); the outer wall (exine) more or less smooth.

The genus differs constantly from Convolvulus in its pollen grains and unilocular ovary, but the European species are most easily distinguished by the pair of broad bracteoles immediately below the sepals.

Key features:-
1) Corolla more than 5 mm, scarcely lobed.
2) Bracteoles broad, leaf-like, partly obscuring the sepals.

CONVOLVULUS

General description:- Annual or perennial herbs or small shrubs up to 100 cm, sometimes with latex.

Stems:- Erect, trailing or twining.

Leaves:- Simple, usually entire.

Flowers:-
Solitary or in terminal or axillary inflorescences; stems (pedicels) with 2 minute to leaf-like bracteoles. Corolla infundibuliform, glabrous except for five usually pubescent stripes often of a different colour. Stamens inserted at the base of the corolla-tube, included. Ovary 2-celled (locular); stigma 2-lobed, the lobes filiform to cylindric-clavate.

Fruit:- Capsule usually 4-seeded, 1- to 2-celled. Pollen grains tricolpate; exine not spinose.

Key features:-
1) Stigma with 2  thread-like (filiform) to cylindric-club-shaped (clavate) lobes.
2) Pollen grains tricolporate, smooth.

CRESSA

General description:- Annual or perennial herbs, often somewhat woody at the base.

Leaves:- Sessile, simple, entire.

Flowers:- In short, terminal, congested racemes; pedicels with 2 small bracteoles. Corolla divided to about halfway into 5 patent, pubescent lobes. Stamens inserted at about the middle of the corolla-tube, glabrous, exserted. Ovary 2-locular; styles 2, exserted; stigmas capitate.

Fruit:- Capsule usually 1-seeded. Pollen grains tricolpate; exine not spinose.

CUSCUTA


General description:- Herbaceous parasites, usually annual.

Stems:- Twining, with suckers (haustoria).

Leaves:- Reduced to minute scales.

Flowers:- Inflorescences cymose, spike-like, umbellate or capitulate. Flowers (3-)4- to 5-merous, small, white, yellowish or reddish. Stamens inserted in throat of corolla-tube. Hypostaminal scales attached at base of corolla-tube opposite the stamens. Ovary 2-celled, each cell containing 2 anatropous ovules. Styles free or united. Stigmas capitate or elongate.

Inflorescences with capitulate cymes are referred to as glomerules. Mature flowers are essential for identification.

Fruit:- A circumscissile capsule splitting open to release the seeds (dehiscing) by an irregular or regular line near base, or remaining closed. Seeds 4 or fewer. Embryo filiform, surrounded by a cartilaginous endosperm. Cotyledons rudimentary or absent.


Key features:-
1) A twining parasite with nutrient absorbing outgrowths (haustoria), not green, more or less hairless (glabrous).

DICHONDRA


General description:- Creeping perennial herb rooting at the nodes.

Leaves:- Petiolate, simple, entire.

Flowers:- Axillary, solitary. Corolla divided to about halfway into 5 erect lobes. Stamens inserted near the top of the corolla-tube, more or less included. Ovary 2-locular; styles 2; stigmas capitate.

Fruit:- Capsule 2-lobed; lobes usually 1-seeded.

IPOMOEA 

General description:- Annual or perennial herbs

Stems:-
Long, trailing or climbing.

Leaves:- Entire or lobed, alternate; petioles long, distinct.

The leaves in all species may vary considerably in shape, usually being entire near the base of the plant and variously lobed towards the apex. The descriptions cover most of this variation, but ignore the lowest leaves which are often very aberrant.

Flowers:- solitary or in axillary cymes, usually with 2 very small bracteoles. Corolla at least 25 mm, funnel-shaped (infundibuliform) or tubiform, scarcely lobed, more or less glabrous. Ovary 2- to 4-locular; ovules usually 2 in each loculus; style filiform; stigma with 1-3 globose lobes.

Fruit:- Capsule usually 4-seeded. Pollen grains with rounded pores all over the surface (pantoporate); the outer wall (exine) spinose.

Key features:-
1) Bracteoles lanceolate to thread-like (filiform), not or scarcely obscuring the sepals.
2) Stigma with 1-3 globose lobes.
3) Pollen grains pantoporate, spinous.

Sect. LEIOCALYX

General description:- Glabrous, without underground tubers.

Stems:- Creeping to weakly climbing.

Flowers:- Sepals acute to rounded, mucronate.