The unusual occurrence of tricolpate pollen within Mutisieae (Asteraceae)

TELLERIA, M.C.; KATINAS, L.

GRANA

Taylor & Francis Journals, London

Lugar: Stockholm; Año: 2005 vol. 44 p. 91 - 97

0017-3134

The monotypic genus Hecastocleis and species of Ainsliaea (Asteraceae, Mutisieae) have tricolpate pollen which is unusual in Asteraceae. The pollen morphology of H. shockleyi and species of Ainsliaea were studied with light microscope and scanning electron microscope. Pollen of H. shockleyi  and some species of Ainsliaea have tricolpate aperture but differ in size and exine features. The pollen of Ainsliaea is bigger than that of Hecastocleis, and has more conspicuous microspines, a Mutisia or an Ainsliaea exine type, and is slightly thickened at the poles. The pollen of H. shockelyi is scabrate-microechinate with small puncta, and the Mutisia exine type which is regularly thickened over the complete grain. The occurrence of tricolpate pollen supports previous authors´ ideas that Hecastocleis and Ainsliaea stand apart from other genera of Mutisieae, but the occurrence of Mutisia exine type does not suggest complete independence of the tribe.