T A X O N O M Y
Monocolpate Grains
Picture of a monocolpate pollen grain from Amaryllis displaying reticulate sculpturing (left) and a polyplicate grain from Ephedra (right). Ephedra is a bushy coniferous desert plant with bristly stems and diminutive leaves.
Some gymnosperm trees such as the cycads and ginkgo produce pollen grains with no apparent aperture. A distinguishable fold, or colpus, however, marks these. Those grains are referred to as monocolpate. Many monocotyledonous angiosperms also produce monocolpate grains. Numerous folds however, characterize some gymnosperm plant pollen grains, such as the ones from Ephedra. These grains are referred to as polyplicate. Monocolpate and polyplicate grains are common in the fossil record beginning from the Triassic and are occasionally encountered in Paleozoic sediments.
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