[4] Of the genera encompassed by the Crassulaceae family, Sedum is the most species rich, the most morphologically diverse and most complex taxonomically.

Telephieae Umbilicieae Semperviveae Aeonieae Sedeae (Leucosedum+Acre) There are now thought to be approximately 55 European species in the genus.

Nikulin and colleagues (2016) have recommended that, given the monophyly of Aeonieae and Semperviveae, species of Sedum outside of the tribe Sedeae (all in subgenus Gormania) be removed from the genus and reallocated.

[17] Various attempts have been made to subdivide this large genus, in addition to segregating separate genera, including creation of informal groups, sections, series and subgenera.

Gray (1821) divided the 13 species known in Britain at that time into five sections; Rhodiola, Telephium, Sedum, (unnamed) and Aizoon.

[18] In 1921, Praeger established ten sections; Rhodiola, Pseudorhodiola, Giraldiina, Telephium, Aizoon, Mexicana, Seda Genuina, Sempervivoides, Epeteium and Telmissa.

[20] In contrast, Fröderströmm (1935) adopted a much broader circumscription of the genus, accepting only Sedum and Pseudosedum within the Sedoideae, dividing the former into 9 sections.

[9] In the Levant, one species of this succulent (S. microcarpum) covers the stony ground like a carpet where the soil is shallow, growing no higher than 5–10 cm.

[citation needed] Sedum lanceolatum is the host plant of the more common Parnassius smintheus found in the Rocky Mountains.

Numerous hybrid cultivars have been developed, of which the following have gained the Royal Horticultural Society's Award of Garden Merit:[b] The leaves of most stonecrops are edible,[45] excepting Sedum rubrotinctum, although toxicity has also been reported in some other species.

[47] Sedum reflexum, known as "prickmadam", "stone orpine", or "crooked yellow stonecrop", is occasionally used as a salad leaf or herb in Europe, including the United Kingdom.

Sedum divergens, known as "spreading stonecrop", was eaten by First Nations people in northwest British Columbia.

[49] Biting stonecrop (Sedum acre) contains high quantities of piperidine alkaloids (namely (+)-sedridine, (−)-sedamine, sedinone and isopelletierine), which give it a sharp, peppery, acrid taste and make it somewhat toxic.

[52] Examples include Ford's Dearborn, Michigan Truck Plant, which has a living roof with 454,000 square feet (42,200 m2) of sedum.

[53] The Rolls-Royce Motor Cars plant in Goodwood, England, has a 242,000 square feet (22,500 m2) roof complex covered in Sedum, the largest in the United Kingdom.

[56] Berlin's Prenzlauer Allee,[57] Le Mans, and Warsaw, for example, plant sedum in between rails of some tramways as a low maintenance alternative to grass.