Pollination rigida", this allows the plant to self-pollinate, which is useful when biotic pollinators in the environment have decreased. It is possible for a plant have varying pollination methods, including both biotic and abiotic pollination. The orchid "Oeceoclades maculata" uses both rain and butterflies, depending on its environmental conditions. More commonly, pollination involves pollinators (also called pollen vectors): organisms that carry or move the pollen grains from the anther of one flower to the receptive part of the carpel or pistil (stigma) of another. Between 100,000 and 200,000 species of animal act as pollinators of the world's 250,000 species of flowering
Pollen DNA barcoding that has grown in popularity due to the decreased costs associated with "next generation sequencing" (NGS) techniques and is being continually improved in efficiency including through the use of a dual-indexing approach. Some of the other major advantages include the savings in time and resources compared to microscopic identification. Identifying pollen is time consuming involving spreading pollen on a slide, staining the pollen to improve visibility, then focusing in on individual pollen grains and identifying them based on size, shape, as well as the shape and number of pores. If a pollen reference library is not available, then pollen has