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Webster 1913 Edition
Thallus
‖
Thal′lus
,Noun.
pl.
Thalli
(#)
. [NL., fr. Gr. [GREEK] young shoot or branch, frond.]
(Bot.)
A solid mass of cellular tissue, consisting of one or more layers, usually in the form of a flat stratum or expansion, but sometimes erect or pendulous, and elongated and branching, and forming the substance of the thallogens.