Phil Bendle Collection:Sedum album (White stonecrop)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Core eudicots
Order: Saxifragales
Family: Crassulaceae
Genus: Sedum
Species: S. album
Binomial name: Sedum album
Common name: White stonecrop

Sedum album is a tufted perennial herb that forms semi-prostrate mat-like stands (7–18 cm high). It is native to the northern temperate regions of the world, often growing in crevices or free-draining rocky soil. It favours alkaline, calciferous soils. Much of the year it grows vegetatively and is densely clad in leaves. 
Though Sedum album is a weak competitor with other plants it thrives on a very thin layer of soil that would not be enough for other plants to grow on.
The plant's fleshy leaves store water and help the plant survive long periods of drought. In drought-stressed plants, Sedum album leaves become covered in a protective reddish pigment. The leaves are alternate, stalkless, blunt-tipped, almost cylindrical, fleshy and glabrous. 
In summer the flowering stems lengthen, become erect and occasionally are branched. The white star-shaped flowers form a dense umbellate cyme (flower cluster). The calyx has five fleshy, round-tipped sepals that are fused at the base. The corolla consists of five regular white petals (0.5–1 cm), ten stamens, a separate gynoecium and five pistils. The fruit has five united, many-seeded follicles.

Sedum album is able to acclimate to its environment depending on the availability of water. It can switch between the metabolic pathways of C3 carbon fixation and that of CAM (crassulacean acid metabolism). CAM is a photosynthetic CO2 fixation pathway that maximizes water use efficiency by only opening the stomata on its leaves at night to allow CO2 to diffuse when the temperature is lower hence reducing evapotranspiration.

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Flowers on their long stems.
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The fleshy leaves that store water.
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Thanks to Wikipedia for text and information:

https://creativecommons.org/licenses/by-sa/3.0/

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