Echeveria

Echeveria is a large genus of flowering plants in the family Crassulaceae, native to semi-desert areas of Central America, Mexico and northwestern South America.
Description.
Plants may be evergreen or deciduous. Flowers on short stalks (cymes) arise from compact rosettes of succulent fleshy, often brightly coloured leaves. Species are polycarpic, meaning that they may flower and set seed many times over the course of their lifetimes. Often numerous offsets are produced, and are commonly known as "hen and chicks", which can also refer to other genera, such as "Sempervivum", that are significantly different from "Echeveria". Many species of "Echeveria" serve important environmental roles, such as those of host plants for butterflies. For example, the butterfly "Callophrys xami" uses several species of "Echeveria", such as "Echevelia gibbiflora", for suitable host plants. Even more, these plants are integral to the oviposition process of "C. xami" and some other butterfly species as well.
Etymology.
"Echeveria" is named for Atanasio Echeverría y Godoy, a botanical illustrator who contributed to "Flora Mexicana".
Taxonomy.
The genus was erected by A. P. de Candolle in 1828, and is named after the 18th century Mexican botanical artist Atanasio Echeverría y Godoy. , the genus consists of about 150 species, including genera such as "Oliveranthus" and "Urbinia" that have formerly been split off from "Echeveria". Molecular phylogenetic studies have repeatedly shown the genus not to be monophyletic: species of "Echeveria" cluster with species of "Cremnophila", "Graptopetalum", "Pachyphytum", and "Thompsonella" as well as species of "Sedum" sect. "Pachysedum". The former "Urbinia" species do appear to form a monophyletic group within this grouping. Although it is clear that "Echeveria" is not monophyletic, its limits are not clear, and further analyses are needed to determine whether and how the genus should be split, or if it should be included in an expanded concept of "Sedum".
Species.
One source accepts the following species:
Cultivation.
Many "Echeveria" species are popular as ornamental garden plants. They are drought-resistant, although they do better with regular deep watering and fertilizing. Most will tolerate shade and some frost, although hybrids tend to be less tolerant. Most lose their lower leaves in winter; as a result, after a few years, the plants lose their compact appearance and need to be re-rooted or propagated. In addition, if not removed, the shed leaves may decay, harboring fungus that can then infect the plant.
Propagation.
They can be propagated easily by separating offsets, but also by leaf cuttings, and by seed if they are not hybrids.
Cultivars and Hybrids.
"Echeveria" has been extensively bred and hybridized. The following is a selection of available plants.
Award winning.
The following have gained the Royal Horticultural Society’s Award of Garden Merit: 