A Historical Perspective on Orchid Pollinium and Pollen Characters

Abstract

Pollinium characters have been among the most important in orchid classification since the first systems were proposed at the beginning of the nineteenth century. The first features to be used were texture, composition, and shape. Accessory structures such as stalks were also noted very early. As more orchid species were described in the early nineteenth century, additional variation was recognized and soon pollinium number and arrangement were used as taxonomic characters. Although established early on, most of these characters have been refined since, such that more character states are now known and there is a better basis for decisions on homology. Improved microscopical techniques facilitated the development of additional pollinium characters such as pollen surface structure and number of apertures. Along with the discovery and use of this variation in orchid classifications, a realization of its relevance to the life history of orchids has also grown.