General description:- Annual, biennial or perennial herbs, rarely small shrubs.
Leaves:- Undivided, exstipulate, more or less succulent.
Flowers:- Regular, usually in cymes, less often in spikes or racemes or solitary in the leaf-axils. Sepals 3 to c. 20, united or free; petals as many, united or free; stamens inserted on the receptacle below and free from the ovary (hypogynous) or united with the petals (epipetalous), equal in number to the petals or, more frequently, twice as many. Carpels superior, equal in number to the petals, free or slightly united (connate) at the base, developing into follicles. Scale-like nectaries usually present between the stamens and carpels.
CRASSULA
General description:- Small, glabrous annuals (outside Europe including perennials and shrubs),
Leaves:- Opposite, connate, often reddish.
Flowers:- 3- to 5-merous. Petals free. Stamens equal in number to the petals.
1) Stamens equal in number to the petals.
2) Leaves opposite, connate.
3) Petals 3 or 4 (rarely 5).
The characteristic habitat of the native European species is ground flooded in winter and dry in summer.
ROSULARIA
General description:- Perennials.
Leaves:- Forming a basal rosette of sessile leaves and several peduncles arising from their axils.
Flowers:- 5-merous, numerous, in a terminal, bracteate raceme or panicle. Calyx small; corolla tubular or campanulate, sympetalous; lobes more or less erect. Stamens (5-)10, epipetalous; filaments short. Follicles slender.
Key features:-
1) Basal leaves oblong-spathulate, sessile.
SEDUM
Leaves:- Usually alternate, seldom crowded into rosettes, and rarely into the dense, globose rosettes.
Flowers:- Inflorescence usually cymose. Flowers hermaphrodite, usually 5-merous, but sometimes 4- or 6- to 9-merous. Petals free or slightly united (connate) at the base, usually patent. Stamens usually twice as many as the petals, sometimes equal in number. Carpels equal in number to the petals.
1) Leaves not connate; mostly cauline; awl-shaped (tapering from the base to the apex) (subulate). ± terete.
2) Petals 5 (rarely 4).
3) Inflorescence cymose.
4) Flowers usually 5-merous, hermaphrodite; pink, white or blue.
5) Rhizome slender and leafless, or absent.
Most European species occur on dry, rocky or stony ground.
S. ACRE Group
General description:- Perennials
Stems:- With short non-flowering shoots and flowering up to 20 cm, but often less.
Leaves:- 3-10(-15) mm, obtuse to subacute, usually thick, often more or less terete, usually spurred at the base.
Flowers:- Inflorescence a terminal cyme, the bracts often leaf-like. Flowers 5-merous. Sepals unequal. Petals yellow, patent. Stamens 10.
Fruit:- Follicles gibbous, stellate-patent.
UMBILICUS
General description:- Perennials, with tuberous or rhizomatous rootstock.
Leaves:- Basal petiolate, usually suborbicular, at least 2 cm diam, hairless (glabrous). Cauline leaves much smaller.
Flowers:- 5-merous, numerous, in a terminal, bracteate raceme or panicle. Calyx small; corolla tubular or bell-shaped (campanulate), petals united (sympetalous); lobes more or less erect. Stamens (5-)10, united with the petals (epipetalous); filaments short.
Fruit:- Follicles slender.
Key features:-
1) Petals 4 or 5, free, or united for considerably less than ½ their length.
2) Leaves mostly basal.
3) Cauline leaves much smaller.
5) Inflorescence racemose.
6) Basal leaves petiolate, not spiny.
7) Corolla tubular, with erect lobes