prothallus
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pro·thal·lus
(prō-thăl′əs) or pro·thal·li·um (-thăl′ē-əm)n. pl. pro·thal·li (-thăl′ī) or pro·thal·li·a (-thăl′ē-ə)
A small, flat, delicate structure produced by a germinating spore and bearing sex organs. It is the gametophyte of ferns and some other plants.
pro·thal′li·al (-lē-əl) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
prothallus
(prəʊˈθæləs) orprothallium
n, pl -li (-laɪ) or -lia (-lɪə)
(Botany) botany the small flat free-living gametophyte that bears the reproductive organs of ferns, horsetails, and club mosses. It is either a green disc on the soil surface or it is colourless and subterranean
[C19: from New Latin, from pro- before + Greek thallos a young shoot]
proˈthallic, proˈthallial adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
pro•thal•li•um
(proʊˈθæl i əm)n., pl. -thal•li•a (-ˈθæl i ə)
the gametophyte of ferns and related plants.
pro•thal′li•al, pro•thal′lic, pro•thal′line (-ˈθæl in, -aɪn) adj.
pro•thal′loid, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.