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A cluster of sporangia on the lower surface of a fertile fern leaf.
A clump of reproductive bodies or spores in lower plants.



in plants, a dense cluster of reproductive organs, for example, sporangia in ferns, zoosporangia in the brown alga Laminaria, and oogonia in the brown alga Dictyota.

References in periodicals archive ?
sorus A reproductive structure in certain amoebas, fungi and lichens.
Indusia absent or (1 species) inconspicuous and appearing as tuft of whitish hairs in center of sorus
1 mm long, protruding from the center of the sorus, not easily observed in mature sori; spores echinulate.
appalachianum are often uniformly golden brown (sometimes weakly bicolored), the leaves are often larger and widest near the base ( but not always), the spores are less than 52[micro]m, and there are usually more than 40 sporangiasters per sorus.