isid·​i·​um | \ īˈsidēəm \
plural isidia\ -​ēə \

Definition of isidium

: an outgrowth from the surface of the thallus in certain lichens that resembles a soredium

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History and Etymology for isidium

New Latin, from Isidium, supposed genus of lichens, irregular from Isis genus of gorgonians + Greek eidos form; from the resemblance of lichens that have isidia to gorgonians

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Cite this Entry

“Isidium.” The Dictionary, Merriam-Webster Inc., Accessed 12 December 2019.

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