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Gymnosperms

The gymnosperms are the plant order of non-flowering plants, which are characterised by the fact that their seeds are exposed to the air during all stages of development. In fact the name gymnosperm means 'naked seeds'. The gymnosperms are woody plants with, which are always pollinated by wind, hence their potential for inducing seasonal allergy, and often the seed-bearing structure is a cone. Gymnosperm members include the Cycades (e.g. Sago Palm); Ginkgos; Conifers or Pinales (e.g. Monkey-puzzle, Nutmeg); Cupressaceae , Taxaceae (e.g. Yew); Taxodiaceae (e.g. Redwood) and the Pines or Pinaceae . [ 1 ]


Cypress (Cupressaceae)

Juniperus depreana
Image source: [ 2 ]

The cypress family, Cupressaceae , consists of coniferous shrubs and trees which are widely distributed around the globe. Members of this family include the Juniper, the arborvitae , Cryptomeria and the true cypresses. The true cypresses, for example the Monterey cypress ( Cupressus macrocarpa ), are found in western North America, southern Europe and eastern Asia. They are reinous evergreens with a fragrant, durable wood. American trees of the genus Chamaecyparis , such as the Lawson cypress ( C. lawsoniana ), although not of this family, are also referred to as cypresses. [ 1 ]

 

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  • Japanese Cedar (Cryptomeria japonica)

    Also known as Japanese Redwood or Peacock Pine, Japanese Cedar is a coniferous evergreen, often used as an ornament in gardens and cities, is characterised by a fragrant reddish brown bark, which peels off in long strips. Japanese Cedar is the only species of the genus Cryptomeria , also of the Cupressaceae family. This species is native to, and most common in, eastern Asia. Incense is produced from the leaves and the wood is often used to build ships, furniture and for ornaments. Thrives on acid soil. [ 3 , 4 ]

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  • Western Red Cedar (Thuja plicata)

    Also referred to as the giant arborvitae, British Columbia red cedar or western arborvitae, this evergreen conifer of the cypress family ( Cupressaceae ), is native to the Pacific Coast of North America. These trees are pyramidal in shape and can reach 60 m (200 feet) in height. The reference to red in the name comes from the cinnamon-red/brownish bark which characterises this species of tree. The western red cedar produces egg-shaped or oval cones. [ 4 ]
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Pine ( Pinaceae)

Pinus ponderosa
Image source: [ 2 ]

Pine is the common name for the Pinaceae family, which are resinous woody trees, normally found in northern temperate zones, and characterised by their needlelike, usually evergreen, leaves. The Pinaceae reproduce by means of cones rather than flowers, and have winged seeds suitable for wind distribution. The Pinaceae family is the largest of the Conifers. Genera contained in the pine family include the fir, larch, spruce, hemlock, cedar and Douglas fir as well as the true pines (genus Pinus ). The Pinus genus can be easily identified by its leaf arrangement : in each species a specific number of needles (one to five) is contained within a sheath. Economically, the true pines are one of the most important trees. For example, the Western yellow pine, or ponderosa, ( P. ponderosa ) is second only to the Douglas fir as a commercial timber tree in North America, while the Scotch pine ( P. sylvestris ), which covers virtually all of Europe, is one of the most valuable European timber trees. The Southern yellow, or longleaf pine ( P. palustris ) is commonly used for heavy construction and to make paper pulp. Certain species of pine also produce nuts, known as pine-nuts. [ 1 ]

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[1] The Concise Columbia Electronic Encyclopedia, Third Edition : http://www.encyclopaedia.com
[2]
Martin, Paul S., and Drew, Charles M., 1969. "Scanning electron photomicrographs of southwestern pollen grains."
    Journal Arizona Academy of Sciences 5 ( 3 ): 147 - 176. Palynology Department, University of Arizona : http://geo.arizona.edu/palynology
[3] Michigan State University Extension Database : http://www.msue.msu.edu
[4]
The Encyclopaedia Britannica Online : http://www.britannica.com
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  http://www.hon.ch/Library/Theme/Allergy/Glossary/gymno.html Last modified: Fri Jun 28 2002