gymnosperm (redirected from Gymnosperms)

gym·no·sperm  (jmn-spûrm)

n.

A plant, such as a cycad or conifer, whose seeds are not enclosed within an ovary.

---

[From New Latin Gymnospermae, class name, from Greek gumnospermos : gumnos, naked; see nog^w- in Indo-European roots + sperma, seed; see sperm¹.]

---

gymno·spermous adj.

gymno·spermy n.

---

gymnosperm  (jmn-spûrm)

Any of a group of seed-bearing plants whose ovules are not enclosed in an ovary, but are exposed on the surface of sporophylls or similar structures. Each ovule may contain several eggs, all of which may be fertilized and start to develop in a process known as polyembryony. In most seeds, however, only a single embryo survives. The reproductive structures of many gymnosperms are arranged in cones. The gymnosperms do not form a distinct monophyletic grouping, but simply include all the seed-bearing plants that are not angiosperms. In addition to several extinct groups, there are four very diverse living gymnosperm phyla: the conifers, the cycads, the ginkgo (surviving in a single species), and the gnetophytes. Compare angiosperm. See more at seed-bearing plant.

Thesaurus

Noun

1.

gymnosperm - plants of the class Gymnospermae having seeds not enclosed in an ovary phanerogam, seed plant, spermatophyte - plant that reproduces by means of seeds not spores class Gymnospermae, division Gymnospermophyta, Gymnospermae, Gymnospermophyta - plants having naked seeds not enclosed in an ovary; in some systems considered a class (Gymnospermae) and in others a division (Gymnospermophyta); comprises three subdivisions (or classes): Cycadophytina (class Cycadopsida) and Gnetophytina (class Gnetopsida) and Coniferophytina (class Coniferopsida); in some classifications the Coniferophytina are divided into three groups: Pinophytina (class Pinopsida) and Ginkgophytina (class Ginkgopsida) and Taxophytina (class Taxopsida) progymnosperm - an ancestral fossil type from which modern gymnosperms are thought to have derived welwitschia, Welwitschia mirabilis - curious plant of arid regions of southwestern Africa having a yard-high and yard-wide trunk like a turnip with a deep taproot and two large persistent woody straplike leaves growing from the base; living relic of a flora long disappeared; some may be 700-5000 years old cycad - any tropical gymnosperm of the order Cycadales; having unbranched stems with a crown of fernlike leaves pteridosperm, seed fern - an extinct seed-producing fernlike plant of the order Cycadofilicales (or group Pteridospermae)