Monocolpate grains
Earth History Research Center

The pollen of some gymnospermous trees such as the cycads and ginkgo produce a grain with no apparent aperture, but with a persistent and recognizable fold or "colpus". Such grains are referred to as monocolpate. Many monocotyledonous (single seed leaf, such as lily) angiosperms (flowering plants) also produce monocolpate grains. Examples are common in the lily family, the palms, and numerous others. An additional complication is encountered in some gymnospermous plants such as Ephedra, which are characterized by numerous folds, and are referred to as "polyplicate".

The grains shown above include a monocolpate pollen grain with reticulate (net-like) sculpturing from an Amaryllis on the left and a polyplicate grain from ephedra on the right. Ephedra is a bushy coniferous desert plant with bristly stems and diminutive leaves. It is the source of a powerful drug, ephedrine, used in antihistamines. Monocolpate grains are occasionally encountered in the Paleozoic, but are common beginning in the Triassic and range to Recent in the fossil record.