Acalymmate Calymmate

In compound pollen grains or pollen units the individual grains are held together by different physical means of the pollen wall. Van CAMPO and GUINET (1961) recognized calymmate and acalymmate types. The term calymmate denotes a feature describing a dispersal unit of two or more monads enclosed by a continuous ektexine.

Calymmate

Chlorospatha kolbii Araceae tetrads

Calymmate

Chlorospatha kolbii Araceae tetrads

Acalymmate denotes a feature describing a dispersal unit of two or more monads enclosed by an exine, which is discontinuous at the junctions between the monads, and is absent from the internal walls.

Since these basic types were described a lot of variations have been found, and the question was raised whether the basic distinction can remain (a survey and a detailed discussion was provided by KNOX and McCONCHIE 1986). The micrographs show examples for either a continuous (calymmate) or a discontinuous exine enclosure (acalymmate).

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