Cypress knee 2585883 225650965 2008-07-14T19:05:09Z PurpleHz 2389831 /* External links */ fr: [[Image:CypressKnees.jpg|thumb|right|200px|Taxodium 'knees']] In the biology of trees, a '''cypress knee''' is a distinctive structure in a root of a [[Cupressaceae|cypress]] [[tree]] of any of various species of the subfamily [[Cupressaceae#Classification|Taxodioideae]]. Their function is unknown, but they are generally seen in [[swamp]]s. Some scientists have thought they may help in providing oxygen to the tree and assist in anchoring the tree in the soft, muddy soil. Knees are [[wood]]y projections sent above the normal water level, roughly horizontally from the [[root]]s, with a near-right-angle bend taking them roughly vertically downward into soil, usually passing through water first. One rather popular view of their function is that they provide oxygen to the roots that grow in the low dissolved [[oxygen]] (DO) waters typical of a swamp (see also [[mangrove]]s, which have similar adaptations). However, there is little evidence for this; in fact, swamp-dwelling specimens whose knees are removed continue to thrive. Another more likely function is that of structural support and stabilization. Lowland or swamp-grown cypresses found in flooded or flood-prone areas tend to be buttressed and "kneed," as opposed to cypresses grown on higher ground which may grow with very little taper. Trees that develop these "knees" include the following: * ''[[Glyptostrobus]]'' * [[Taxodium distichum|Bald Cypress]] * [[Taxodium ascendens|Pond Cypress]] ==External links== {{commons-inline|Category:Cypress knees|Cypress knees}} {{conifer-stub}} [[Category:Plant morphology]] [[de:Atemknie]] [[fr:Pneumatophore]]