noun
definition
A protecting membrane, especially that covering the developing spores of a fern.
Examples of indusium in a Sentence
A woollen undergarment (subucula) was often worn by men; the women's under-tunic was of linen (indusium).
Ovular characters determine the grouping in the Dicotyledons, van Tieghem supporting the view that the integument, the outer if there be two, is the lamina of a leaf of which the funicle is the petiole, whilst the nucellus is an outgrowth of this leaf, and the inner integument, if present, an indusium.
Even if we admit van Tieghem's interpretation of the integuments to be correct, the diagnostic mark of his unitegminous and bitegminous groups is simply that of the absence or presence of an indusium, not a character of great value elsewhere, and, as we know, the number of the ovular coats is inconstant within the same family.
The sorus is frequently protected by an outgrowth from the surface or margin of the leaf called the indusium.
The elongated receptacle of the marginal sori is surrounded by a basal cup-shaped indusium.
When mature, the sporangia are raised above the margin of the indusium by the elongation of the receptacle, thus facilitating the dispersion of the spores.
The sori, which are marginal, have a long receptacle, bearing the sporangia in basipetal succession, and are surrounded by a cup-shaped indusium.
The sorus has a somewhat elongated receptacle, on which the sporangia arise basipetally; the indusium may be cup-shaped, bivalve or wanting.
On this view Wheeler, however, compares with the " dorsal organ " the peculiar the entire food-canal in most Hexapoda must be regarded as of extra embryonic membrane or indusium which he has observed ectodermal origin, the " endoblast " represents mesoderm only, between serosa and amnion in the embryo of the grasshopper and the median furrow whence it arises can be no longer compared Xiphidium.