from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A small, flat, delicate structure produced by a germinating spore and bearing sex organs. It is the gametophyte of ferns and some other plants.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A prothallium.

from the GNU version of the Collaborative International Dictionary of English

  • n. The minute primary growth from the spore of ferns and other Pteridophyta, which bears the true sexual organs; the oöphoric generation of ferns, etc.

from The Century Dictionary and Cyclopedia

  • n. Same as prothallium.


New Latin : pro-2 + Greek thallos, shoot (from thallein, to sprout).
(American Heritage® Dictionary of the English Language, Fourth Edition)



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