indusium

American  

[in-doo-zee-uhm, -zhee-uhm, -dyoo-] / ɪnˈdu zi əm, -ʒi əm, -ˈdyu- /

noun

plural

indusia

1. Botany, Mycology. any of several structures having a netlike or skirtlike shape, as the membranous overgrowth covering the sori in ferns.

2. Anatomy, Zoology.

   1. an enveloping layer or membrane.

   2. a thin layer of gray matter on the corpus callosum.

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indusium British  

/ ɪnˈdjuːzɪəm /

noun

1. a membranous outgrowth on the undersurface of fern leaves that covers and protects the developing sporangia

2. an enveloping membrane, such as the amnion

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indusium Scientific  

/ ĭn-do̅o̅′zē-əm,-zhē- /

plural

indusia

1. A thin membrane covering the sorus of a fern. The indusium often shrivels away when spores are ready to be dispersed.

2. Also called fruitcover

3. A cuplike structure fringed with hairs and located at the top of the style in flowers of the family Goodeniaceae (which includes the garden flowers lobelia and scaevola). Pollen is deposited into the indusium by the anthers of the same flower and, as the style grows, carried up for dispersal by pollinating insects.

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Other Word Forms

• indusial adjective

Etymology

Origin of indusium

1700–10; < New Latin; Latin: kind of tunic, perhaps < Greek éndys ( is ) dressing, dress ( endý ( ein ) to put on + -sis -sis ) + Latin -ium, for Greek -ion noun suffix

Example Sentences

Ferns with much divided leaves and short, marginal sori borne at the ends of free-forking veins, on the under side of the reflexed and altered portion of the pinnules, which serves as an indusium.

From The Fern Lover's Companion A Guide for the Northeastern States and Canada by Tilton, George Henry

The wood ferns, on the other hand, have a kidney-shaped indusium attached to the fronds by the sinus.

From The Fern Lover's Companion A Guide for the Northeastern States and Canada by Tilton, George Henry

Pinnules divided into minute, densely crowded segments, the herbaceous margin recurved and forming an almost continuous indusium.

From The Fern Lover's Companion A Guide for the Northeastern States and Canada by Tilton, George Henry

Sori oblong or linear, borne on a veinlet parallel to the midrib, and covered with a special usually concave or arched indusium attached to the fruiting veinlet, and opening along the inner side.

From The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee by Gray, Asa

Sori minute, at the ends of the veins; indusium continuous or interrupted.

From The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee by Gray, Asa