Gymnosperms: Salient Characteristic Features
The gymnosperms are a group of seed-producing plants which are also known as Acrogymnospermae. The term ‘Gymnosperm’ is originated from two Greek words, ‘gymnos’ meaning naked and ‘sperma’ meaning seed. It is a smaller ancient group of plants that produce naked seeds because their seeds are not enclosed by a fruit. On earth, more than 1000 gymnospermic plants species are still found. The notable groups are cycads (Cycas, Lepidozamia, Macrozamia, Zamia, Microcycas, etc), conifers (cypresses, pines, cedars, firs, junipers, larches, redwoods, kauris, etc), gnetophytes (Ephedra, Gnetum, and Welwitschia) and Ginkgo (Ginkgo biloba). Among them, the largest group of living gymnosperms is Conifers while ginkgo is a single living plant species which is found in China. Generally, gymnosperms are plentiful in the temperate forest zone and they can tolerate dry or moist conditions. They have needle-like leaves and most of them are evergreen. In the Himalayas of the Indian subcontinent, they are more abundant and form coniferous forests. Sequoiadendron giganteum (giant saquoia: family-Sequoioideae) is popularly known as a redwood which is the largest conifer species that can grow more than 100 meters in height.
The gymnosperms belong to six phyla:
Among the above six phyla, Pteridospermales and Cordaitales have gone to extinct.
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Salient Characteristic Features of Gymnosperms
Gymnosperms are an archaic group of the naked seeded plant. During the Mesozoic period (225 million years ago), they were most abundant. At present, they form only a small part of green vegetation. They have major economic values due to their various uses. Some gymnospermic conifer plants such as Pine, spruce, fir, and cedar are used for the production of lumber, paper, and resin. Some common items such as food, soap, varnish, gum, nail polish, and perfumes are also produced from many gymnospermic plants.
Some genera of gymnosperms such as Pinus bear fungal association roots (mycorrhiza) which play an important role in plant nutrition, soil chemistry, and soil biology while some other species (Cycas) have coralloid roots which contain cyanobacteria for helping nitrogen fixation.
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