[sawr-uhs, sohr-]
noun, plural sori [sawr-ahy, sohr-ahy] .
Botany. one of the clusters of sporangia on the back of the fronds of ferns. See diag. under fern.
Mycology. a soruslike spore mass of certain fungi and lichens.

1825–35; < Neo-Latin < Greek sōrós heap Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source Link To sorus
World English Dictionary
sorus (ˈsɔːrəs)
n , pl -ri
1.  a cluster of sporangia on the undersurface of certain fern leaves
2.  any of various similar spore-producing structures in some lichens and fungi
[C19: via New Latin from Greek sōros a heap]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
Cite This Source
American Heritage
Science Dictionary
sorus   (sôr'əs)  Pronunciation Key 
Plural sori (sôr'ī)
  1. A cluster of sporangia borne on the underside of a fern frond. A sorus is sometimes covered by an indusium. Also called fruitdot.

  2. A reproductive structure consisting of masses of spores, characteristic of certain fungi such as rusts and smuts.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Encyclopedia Britannica


in botany, brownish or yellowish cluster of spore-producing structures (sporangia) usually located on the lower surface of fern leaves. A sorus may be protected during development by a scale or flap of tissue called an indusium. In rust and smut fungi, a sorus is a spore mass produced on the leaf of an infected plant. Reproductive structures called sori also occur in various species of marine algae. See also spore.

Learn more about sorus with a free trial on

Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
Cite This Source
Related Words
Copyright © 2014, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature