Cone, about 30 cm long The gymnosperms are a group of seed-producing plants () that includes conifers (),,, and. The term 'gymnosperm' comes from the composite word γυμνόσπερμος (γυμνός gymnos, 'naked' and σπέρμα sperma, 'seed'), meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds (called in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (), which are enclosed within an. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form, or solitary as in,, Ginkgo. The gymnosperms and together compose the or seed plants. The gymnosperms are divided into six phyla.

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Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct. By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by, (, and ), and (a single living species). Roots in some genera have fungal association with roots in the form of ( Pinus), while in some others ( Cycas) small specialised roots called coralloid roots are associated with nitrogen-fixing cyanobacteria. Further information: In early classification schemes, the gymnosperms (Gymnospermae) were regarded as a 'natural' group. There is conflicting evidence on the question of whether the living gymnosperms form a. The fossil record of gymnosperms includes many distinctive that do not belong to the four modern groups, including seed-bearing trees that have a somewhat -like vegetative morphology (the so-called 'seed ferns' or.) When fossil gymnosperms such as, Caytonia and the are considered, it is clear that angiosperms are nested within a larger gymnosperm clade, although which group of gymnosperms is their closest relative remains unclear.

For the most recent classification on extant gymnosperms see Christenhusz et al. There are 12 families, 83 known genera with a total of ca 1080 known species (Christenhusz & Byng 2016 ). Subclass • Order • Family: Cycas • Family: Dioon, Bowenia, Macrozamia, Lepidozamia, Encephalartos, Stangeria, Ceratozamia, Microcycas, Zamia. Zamia integrifolia, a cycad native to Florida are by far the most abundant extant group of gymnosperms with six to eight families, with a total of 65-70 genera and 600-630 species (696 accepted names). Conifers are woody plants and most are evergreens. The of many conifers are long, thin and needle-like, other species, including most and some, have flat, triangular scale-like leaves.

In Araucariaceae and in Podocarpaceae have broad, flat strap-shaped leaves. Are the next most abundant group of gymnosperms, with two or three families, 11 genera, and approximately 338 species. Hole Punch In Drivers License. A majority of cycads are native to tropical climates and are most abundantly found in regions near the equator.

The other extant groups are the 95-100 species of and one species of. Uses [ ] Gymnosperms have major economic uses. Pine, fir, spruce, and cedar are all examples of conifers that are used for, paper production, and resin.

Some other common uses for gymnosperms are,,, food, gum, and. Life cycle [ ]. Example of gymnosperm lifecycle Gymnosperms, like all, have a sporophyte-dominant life cycle, which means they spend most of their life cycle with diploid cells, while the (gamete-bearing phase) is relatively short-lived. Two spore types, microspores and megaspores, are typically produced in pollen cones or ovulate cones, respectively. Gametophytes, as with all heterosporous plants, develop within the spore wall. Pollen grains (microgametophytes) mature from microspores, and ultimately produce sperm cells.