Aestivation (botany)

For the meaning of 'animal dormancy' as used in zoology, see Aestivation.

"Crumpled" redirects here. For the deformation feature, see Crumple zone.

File:Aestivation.png

A diagram showing some kinds of petal or sepal aestivation in flower buds. A: quincuncial; B,C: cochleate; D: contorted; E: valvate; F: open.

Aestivation or estivation refers to 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.

The terms used to describe aestivation are the same as those used to describe leaf vernation. Classes of aestivation include:

• 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 plicate
  • quincuncial – with five parts, where two petals or sepals are outside all others, two are inside all others, and the fifth is outside on one margin and inside on the other
• crumpled
• decussate
• induplicate – folded inwards
• open – petals or sepals do not overlap or even touch each other
• reduplicate – folded outwards
• valvate – margins of adjacent petals or sepals touch each other without overlapping.

• Kashira lilacs 01.JPG

  Lilac (Syringa vulgaris), valvate aestivation

• Phlox aestivation.jpg

  Phlox (Phlox paniculata), contorted aestivation

• Vinca minor aestivation.jpg

  Vinca minor, contorted aestivation

• 

  Ipomoea, contortiplicate aestivation

• Starr 070302-5063 Merremia tuberosa.jpg

  The corolla of Merremia tuberosa was contortiplicate in the bud