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 (ĭn-do͞o′zē-əm, -zhē-, -dyo͞o′-)
n. pl. in·du·si·a (-zē-ə, -zhē-ə)
An enclosing membrane, as that covering the sorus of a fern.

[Latin, tunic, perhaps alteration of Greek endusis, dress, from enduein, to sink into, put on : en-, in; see en-2 + duein, to sink.]


n, pl -sia (-zɪə)
1. (Botany) a membranous outgrowth on the undersurface of fern leaves that covers and protects the developing sporangia
2. (Zoology) an enveloping membrane, such as the amnion
[C18: New Latin, from Latin: tunic, from induere to put on]
inˈdusial adj


(ɪnˈdu zi əm, -ʒi əm, -ˈdyu-)

n., pl. -si•a (-zi ə, -ʒi ə)
1. Bot., Mycol. any of several structures having a netlike or skirtlike shape, as the membranous overgrowth covering the sori in ferns.
2. Anat., Zool.
a. an enveloping layer or membrane.
b. a thin layer of gray matter on the corpus callosum.
[1700–10; < New Latin; Latin: kind of tunic]
in•du′si•al, adj.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.indusium - a membrane enclosing and protecting the developing spores especially that covering the sori of a fernindusium - a membrane enclosing and protecting the developing spores especially that covering the sori of a fern
covering, natural covering, cover - a natural object that covers or envelops; "under a covering of dust"; "the fox was flushed from its cover"
sorus - cluster of sporangia usually on underside of a fern frond
References in periodicals archive ?
There appear to be two main players of relevance to Arabian workers: a diploid with entire false indusia, and an allotetraploid with fringed false indusia (Vida et al.
After several days, the contents of the envelopes were sifted with a metallic mesh with openings 0.074 mm in diameter to eliminate the remains of sporangia and indusia. Spores of all species were sown in Petri dishes 5 cm in diameter (20 dishes for each species, with three replicates for each species) containing previously sterilized agar with Thompson's nutrients (Klekowski, 1969; Mendoza-Ruiz & Perez-Garcia, 2005).
sprucei it is formed by cells with thickened walls, in a polygonal pattern, different of the indusia described for other species of the genus (Prada and Rolleri 2006b, and unpublished data).
Sori marginal, under revolute margins of blade; indusia absent 12
Leaf stalk (petiole) essentially lacking scales (may have a few near base); indusia hood-like: Cystopteris
Sori elongate; sporangia minutely hairy; indusia absent; plant of sandstone bluffs: T.
It is similar to Hay-scented Fern (Dennstaedtia punctilobula), but leaves are 4-pinnate-pinnatifid (instead of 2-pinnate-pinnatifid in Dennstaedtia) and has "flaps" (false outer indusia) that cover the sori along margins of the leaflets.