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

Much like the last, but the rather larger fronds puberulent beneath with minute jointed hairs and stalked glands; indusium deeply cleft into narrow segments ending in jointed hairs.—Rocky places, Minn., southward and westward.

From Project Gutenberg

Wheeler, however, compares with the “dorsal organ” the peculiar extra embryonic membrane or indusium which he has observed between serosa and amnion in the embryo of the grasshopper Xiphidium.

From Project Gutenberg

In Maidenhair-Ferns a little lobe of the leaf is folded back over each fruit-dot, to serve as its shield or indusium.

From Project Gutenberg

When the fruit is ripe, the indusium is something of a lilac colour, spotting the frond in double rows—as you see it there.

From Project Gutenberg

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

From Project Gutenberg