thorn

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thorn

thorn sharp-pointed projection on some plants, usually protective in function. Botanically, thorns are distinguished as modified stems (as in the honey locust and hawthorn) from spines, which are modified leaves (as in the barberry), and from prickles, which are epidermal outgrowths of the bark (as in the rose and blackberry). Cacti have both thorns and spines.

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thorn

A Dictionary of Biology | 2004 | Â© A Dictionary of Biology 2004, originally published by Oxford University Press 2004. (Hide copyright information) Copyright

thorn A hard side stem with a sharp point at the tip, replacing the growing point. In some plants the development of thorns and subsequent suppression of the growing points may be a response to dry conditions. Examples are the thorns of gorse and hawthorn. Compare prickle; spine.

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thorn

A Dictionary of Plant Sciences | 1998 | | Â© A Dictionary of Plant Sciences 1998, originally published by Oxford University Press 1998. (Hide copyright information) Copyright

thorn A woody, projecting structure with a sharp point that is derived from the leaf, stem, or branch of the plant and is connected to its vascular system.

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MICHAEL ALLABY. "thorn." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 24 Dec. 2009 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "thorn." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (December 24, 2009). http://www.encyclopedia.com/doc/1O7-thorn.html

MICHAEL ALLABY. "thorn." A Dictionary of Plant Sciences. 1998. Retrieved December 24, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-thorn.html

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