A search for phylogenetically informative pollen characters in the subtribe Salviinae (Mentheae : Lamiaceae)

Publication Type:Journal Article
Year of Publication:2008
Authors:H. - K. Moon, Vinckier, S., Walker, J. B., Smets, E., Huysmans, S.
Journal:International Journal of Plant Sciences
Date Published:Jan
Keywords:Distyly, Grains, Labiatae, Morphology, Orbicules, Palynology, Perovskia, Phylogeny, Pollen Dimorphism, Salviinae, Systematics

The pollen morphology and ultrastructure of the subtribe Salviinae were investigated with light, scanning electron, and transmission electron microscopy. In addition, cladistic analyses of the obtained morphological data, supplemented with rbcL data from GenBank, were conducted in order to assess the phylogenetic signal of palynological characters. Salviinae pollen is small to large, oblate to prolate in shape, with a circular to slightly elliptic amb, and mostly hexacolpate. Perovskia abrotanoides appears to be distylous and shows a significant pollen dimorphism between pin and thrum flowers. The sexine ornamentation of the genera Lepechinia and Chaunostoma is perforate, while the ornamentation of other genera is bireticulate. Perovskia expresses a unique type of sexine ornamentation. The sexine ornamentation variation in Salvia has systematic importance but only partly corresponds with current phylogenetic hypotheses. Unbranched columellae and a continuous, granular endexine are hypothesized to be a symplesiomorphic condition in the tribe Mentheae. Our combined phylogenetic analyses show that the addition of palynological characters contributes to improved resolution and also increases bootstrap support values in comparison with molecular phylogenetic analyses.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith