Summarizing Gymnosperms

Summary

Gymnosperms are heterosporous seed plants that produce naked seeds. They appeared in the Paleozoic period and were the dominant plant life during the Mesozoic. Modern-day gymnosperms belong to four phyla. The largest phylum, Coniferophyta, is represented by conifers, the predominant plants at high altitude and latitude. Cycads (phylum Cycadophyta) resemble palm trees and grow in tropical climates. Gingko biloba is the only representative of the phylum Gingkophyta. The last phylum, Gnetophyta, is a diverse group of shrubs that produce vessel elements in their wood.

Glossary

conifer

dominant phylum of gymnosperms with the most variety of trees

cycad

gymnosperm that grows in tropical climates and resembles a palm tree; member of the phylum Cycadophyta

dioecious

describes a species in which the male and female reproductive organs are carried on separate specimens

gingkophyte

gymnosperm with one extant species, the Gingko biloba: a tree with fan-shaped leaves

gnetophyte

gymnosperm shrub with varied morphological features that produces vessel elements in its woody tissues; the phylum includes the genera Ephedra, Gnetum and Welwitschia

gymnosperm

seed plant with naked seeds (seeds exposed on modified leaves or in cones)

integument

layer of sporophyte tissue that surrounds the megasporangium, and later, the embryo

megasporocyte

megaspore mother cell; larger spore that germinates into a female gametophyte in a heterosporous plant

microsporocyte

smaller spore that produces a male gametophyte in a heterosporous plant

monoecious

describes a species in which the male and female reproductive organs are on the same plant

ovulate cone

cone containing two ovules per scale

strobilus

plant structure with a tight arrangement of sporophylls around a central stalk, as seen in cones or flowers; the male strobilus produces pollen, and the female strobilus produces eggs