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Dryad

Data from: Understanding the systematic implications of pollinium morphology of Aeridinae (Orchidaceae)

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Aug 18, 2024 version files 178.22 KB

Abstract

Molecular phylogenetic studies have suggested major clades in the subtribe Aeridinae of Orchidaceae. However, systematic morphological charaters is still lacking. We carried out this study on the pollinium morphologies of subtribe Aeridinae with emphases on the aperture types and the pollinium sculpture to find out their systematic signification in light of a molecular phylogeny. The results indicate that most species have cleft type and few with porate type or none. The shapes of most pollinium are flat spheroid but not constant at genera levels. The longth scope of the pollinium is 204-2606 um and the width scope is 178-1524 um. The long and wide pollinium are easily found in more primitive groups. The short and narrow pollinium are commonly found in more evolutionary groups. Shapes and sizes of individual units of pollinium vary from uniformity to difference with few exceptions: isometrical polygons in Phalaenopsis of Phalaenopsis clade, Vanda clade and Aerides clade and irregular shape and different sizes in rest samples. Individual units of most pollinium are tetrads and individual pollen grains are easy to distinguish within the tetrad. The degree of discriminability of individual pollen grains is constant at clades level and changes following a tendency except Aerides rosa: unrecognizable in Chiloschista clade - easily distinguished in Phalaenopsis clades, VandaAerides and Gastrocohilus clades - partly distinguished in Trichoglottis and Cleisostoma clade. Exine sculpture characters are consistent in each clades except Cleisostoma clade and Phalaenopsis clade. It has a somewhat clear changing tendency in consist with the molecular phylogeny with few exceptions: from negative reticulum of Phalaenopsis clade - reticulum of Chiloschista clade - levelled psilate surface of Vanda and Aerides clades  bulgy with psilate surface in Gastrocohilus and Trichoglottis clades - two types in Cleisostoma clade. Conclusionarily, these pollinium characters are not systematic but useful characters in determining major systematic groups in subtribe Aeridinae.