[ proh-thal-uhs ]

noun,plural pro·thal·li [proh-thal-ahy]. /proʊˈθæl aɪ/. Botany.

Origin of prothallus

From New Latin, dating back to 1850–55; see origin at pro-2, thallus

Words Nearby prothallus Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use prothallus in a sentence

British Dictionary definitions for prothallus


prothallium (prəʊˈθælɪəm)

/ (prəʊˈθæləs) /

nounplural -li (-laɪ) or -lia (-lɪə)
  1. 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

Origin of prothallus

C19: from New Latin, from pro- before + Greek thallus a young shoot

Derived forms of prothallus

  • prothallic or prothallial, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for prothallus


[ prō-thăləs ]

Plural prothalli (prō-thălī)
  1. The gametophyte of homosporous ferns and some other plants. Prothalli have chlorophyll for photosynthesis, but they are not differentiated into roots, stems, or leaves. They are usually small, flat, and delicate. Prothalli develop from germinated spores, and they bear both archegonia for producing eggs and antheridia for producing sperm. See more at alternation of generations.

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