Gymnosperm

Gymnospermae
White spruce leaves (needles)
Scientific classification
Kingdom:	Plantae
(unranked):	Spermatophyta
(unranked):	Gymnospermae
Divisions
Pinophyta (or Coniferophyta) – Conifers Ginkgophyta – Ginkgo Cycadophyta – Cycads Gnetophyta – Gnetum, Ephedra, Welwitschia

The gymnosperms are a group of tree plant which includes tales.^[1]

They have naked seeds, in contrast to the seeds or ovules of flowering plants (angiosperms) which are enclosed during pollination. Gymnosperm seeds develop either on the surface of scale- or leaf-like appendages of cones, or at the end of short stalks (Ginkgo).^[2]

The gymnosperms and angiosperms together make up the spermatophytes or seed plants. By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, Gnetales (Gnetum, Ephedra and Welwitschia), and Ginkgo (a single living species).^[3]

Fossil gymnosperms include many that do not belong to the four modern groups, including the so-called "seed ferns" (Pteridosperms) and the "cycadeoids" (Bennettitales). Most of the Gymnosperms became extinct in the Cenozoic era (from 65 million years ago to present day).^[4]

Some genera have mycorrhiza, fungal associations with roots (Pinus). In some others (Cycas) small specialised roots have nitrogen-fixing cyanobacteria.

1. ↑ The term comes from the Greek word (γυμνός) for "naked seed", gymnospermos.
2. ↑ Anderson, Anderson & Cleal 2007. Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology. Strelitzia. 20 SANBI. p280. ISBN 978-1-919976-39-6
3. ↑ Walas, Łukasz; Mandryk, Wojciech; Thomas, Peter A.; Tyrała-Wierucka, Żanna; Iszkuło, Grzegorz (2018-09-01). "Sexual systems in gymnosperms: A review". Basic and Applied Ecology. 31: 1–9. doi:10.1016/j.baae.2018.05.009. ISSN 1439-1791. S2CID 90740232.
4. ↑ Crisp, M.D.; Cook, L.G. (2011). "Cenozoic extinctions account for the low diversity of extant gymnosperms compared with angiosperms". New Phytologist. 192 (4): 997–1009. doi:10.1111/j.1469-8137.2011.03862.x. PMID 21895664. S2CID 23823843.{{cite journal}}: CS1 maint: multiple names: authors list (link)