Klappblätter

Klappblätter is a German term with two principal meanings in different fields: botany and publishing.

In botany and plant morphology, Klappblätter describes a leaf blade or leaflet that is hinged and capable of folding along a defined line. This folding can be automatic as part of leaf movements (nyctinasty or thigmonasty) or occur in response to growth and development. The hinge region may involve pulvini or other specialized tissues that enable the blade to bend. The term is descriptive and used in botanical descriptions to convey the folded or hinged nature of certain leaves or leaflets, particularly in the context of compound leaves or leaf architecture.

In publishing and printing, Klappblätter refer to fold-out leaves or flaps inserted into a book or document. These sheets can carry maps, diagrams, charts or extended text that would not fit on a standard page. Fold-outs are common in atlases, field guides, architectural plans and older or reference works. They are typically attached along one edge and can be unfolded for viewing, then refolded to keep the volume compact.

The two usages share the same etymology from klappen (to fold) and Blatt (leaf). The term is mainly descriptive and cross-disciplinary, with no single universal definition beyond the folding or hinged nature implied by its components.