indusium

American  

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

noun

indusia plural

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.

---

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

---

indusium Scientific  

/ ĭn-do̅o̅′zē-əm,-zhē- /

indusia plural

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.

---

Other Word Forms

Derived Forms

• indusial
  adjective

Inflected Forms

Nouns

• indusia
  plural

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

See Examples For:

indusium indusia

Sporangia borne on an elevated, globular receptacle in a membranous, cup-shaped indusium which is open at the top.

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

Sori round, borne on the veins; indusium fixed under the sorus, divided into segments or into slender filaments.

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 more or less elongated, without indusium, placed on the back of the frond, usually along the veins or near their extremities.

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

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 Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" by Various

Sori roundish or elongated and extending far down the free veins, at first covered by the very broad continuous indusium, at length exposed and confluent.

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

Pinnules toothed or entire nearly covered beneath with the large, thin, imbricated indusia which are orbicular with a narrow sinus, having the margins ragged and sparingly glanduliferous.

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

Although the genus Polýstichum represents the true shield ferns, the wood ferns are also thus designated, as their indusia have nearly the shape of small, roundish shields.

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

Sporangia near or on the margin of the segments, the reflexed portions of which serve as indusia.

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

It is one of our handsomest evergreen ferns and even the large sori, with their dark spore cases and white indusia, are very attractive.

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

Sporangia borne on elevated receptacles, forming roundish sori imperfectly covered by very delicate hood-shaped indusia attached to the base of the receptacles.

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