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Cochleate
Aestivation or estivation is the positional arrangement of the parts of a flower within a flower bud before it has opened. Aestivation is also sometimes referred to as praefoliation or prefoliation, but these terms may also mean vernation: the arrangement of leaves within a vegetative bud. Aestivation can be an important taxonomic diagnostic; for example Malvaceae flower buds have valvate sepals, with the exception of the genera ''Fremontodendron'' and ''Chiranthodendron'', which have sometimes been misplaced as a result. Terminology The terms used to describe aestivation are the same as those used to describe leaf vernation. Classes of aestivation include: * ''crumpled'' * ''Glossary of botanical terms#D, decussate'' * ''imbricate'' – overlapping ** ''contorted'' or ''twisted'' – every petal or sepal is outside its neighbour on one margin, and inside its neighbour on the other margin. *** ''cochleate'' – spirally twisted. *** ''contortiplicate'' – contorted and also G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aestivation
Aestivation ( la, aestas (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a lowered metabolic rate, that is entered in response to high temperatures and arid conditions. It takes place during times of heat and dryness, the hot dry season, which are often the summer months. Invertebrate and vertebrate animals are known to enter this state to avoid damage from high temperatures and the risk of desiccation. Both terrestrial and aquatic animals undergo aestivation. Fossil records suggest that aestivation may have evolved several hundred million years ago. Physiology Organisms that aestivate appear to be in a fairly "light" state of dormancy, as their physiological state can be rapidly reversed, and the organism can quickly return to a normal state. A study done on '' Otala lactea'', a snail native to parts of Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
