Diversity: A family of 35 genera and over 1500 species of annual and perennial (mostly) herbs and some shrubs. Mostly xerophytes that sequester water in the leaves producing a fleshy leaf succulence, manifested by many 'rock garden' taxa in this family. Many genera also show an unusual (present in about 5% of the flowering plant species - ca. 18 families) physiological feature, "Crassulacean acid metabolism (CAM)", that allows gas exchange (CO2 acquisition and conversion to organic acids) to occur at night, via open stomata (pores in the leaves - see page from Utah State) and, during the day when the stomata are closed, the CO2 released and used immediately in photosynthesis. As a result, the plant is able to conserve water.
Distribution: World wide, but most diverse in southern Africa - we have 7 genera witrh 16 species in Texas.
Vegetative characters include fleshy, succulent leaves that often show
a three-dimensional (as opposed to laminar) form, either opposite or
Generic variation with regard to perianth part numbers and connation;
usually twice the number of perianth parts, and the gynoecium usually
(some basal fusion) with each carpel subtended by a nectar-producing
and the fruit a follicle.
|Sedum nuttallianum - rare local species (sandy areas) of the largest Genus.||Sedum nuttallianum - succulent leaves, sepals - and apocar|
|4-merous, connate flower (left) and inflorescence (right - UH Botany) of Kalanchoe|
More information on the Crassulaceae