Gymnosperms are plants that do not flower and do not bear their seeds in an enclosure such as a fruit. The seeds are produced on the surface of the sporophylls or similar structures until they are dispersed. The sporophylls are usually arranged in a spiral on the female strobili (cones) that develop at the same time as the smaller male strobili. The male strobili produce the pollen which will fertilize the ovules in the female cones. The ovule contains a nutritious nucellus that is itself enclosed in several layers of the integument. The integument layers will eventually become the seed coat, after fertilization and further development of the embryo takes place.
Gymnosperms are classified into one division and three subdivisions: Division Pinophyta with Subdivision Cycadicae, which includes the palm-like cycads; Subdivision Pinicae, which includes conifers and class Ginkgoatae the Ginko trees; and Subdivision Gneticae, which includes the gnetophytes.