Desiccation

thumb|Mudcrack|Desiccation cracks in [[sludge]] thumb|Centripetal desiccation cracks in the Lower Jurassic [[Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, southwestern Utah. A dinosaur footprint is at the center.]]

species of plant

upright=1.25|thumb|Fresh mudcracks on the shore of The Wash, England Mudcracks (also known as mud cracks, desiccation cracks or cracked mud) are sedimentary structures formed as muddy sediment dries and contracts. Crack formation also occurs in clay-bearing soils as a result of a reduction in water content.

Poikilohydry is the lack of ability (structural or functional mechanism) to maintain and/or regulate water content to achieve homeostasis of cells and tissue connected with quick equilibration of cell/tissue water content to that of the environment. The term is derived from Ancient Greek ποικίλος (poikílos, “spotted or variegate”).