What is false indusium?
function in ferns In fern: The indusium. One is the so-called false indusium, a rolled-over leaf margin under which sporangia form and mature. The true indusium is a separate and unique formation, the structural origins of which are not clear, that constitutes a more or less papery covering over the sorus.
What is false indusium in pteris?
In the figure, solid red circle –false indusium originating from the margins. 1. It is formed by the curving of margins of the pinnae or leaflet that protects the marginal sorus.
What is the relationship between a Sorium and an indusium?
structure in ferns protective flap of tissue (indusium), which is attached laterally along the inner side of the sorus. The spores are mostly bean-shaped (bilateral).
What is indusium in sorus?
Indusium is the rolled-over leaf margin, a protective cover formed over sorus. The sporangia form and mature under the indusium. This type of indusium is called a false indusium. A true indusium is unique and has a separate formation.
What is the function of the indusium?
A flap of tissue that protects the sori in some ferns. This can take a variety of forms. When spores are mature and ready for release, the indusia usually shrivel or bend backwards to expose the sporangia.
What is annulus and Stomium?
ring, the annulus, is prominent on the back and apex of the spo- rangium and is attached to the pedicel at the rear. From the annulus to the front of the pedicel a number of thin-walled cells complete the ring. Two of these cells meet in a straight line, the stomium (S, Fig.
What do you mean by indusium?
Definition of indusium : an investing outgrowth or membrane especially : an outgrowth of a fern frond that covers the sori.
What is indusium in biology?
indusium in British English 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.
What is the function of indusium?
Answer: A flap of tissue that protects the sori in some ferns. This can take a variety of forms. When spores are mature and ready for release, the indusia usually shrivel or bend backwards to expose the sporangia.
What is indusium pteridophytes?
indusium in British English 1. a membranous outgrowth on the undersurface of fern leaves that covers and protects the developing sporangia.
What is a Stomium?
Definition of stomium 1 : the thin-walled cells of the annulus marking the line or region of dehiscence of a fern sporangium. 2 : the opening in an anther usually between lip cells through which dehiscence occurs.
What is annulus in Pteridophytes?
In leptosporangiate ferns, the annulus located on the outer rim of the sporangium and serves in spore dispersal. It consists typically of a ring or belt of dead water-filled cells with differentially thickened cell walls that stretches about two-thirds around each sporangium in leptosporangiate ferns.
Where is indusium on a fern?
The indusium is round, shaped like a tiny umbrella and attached to the leaf from the middle. These sword fern indusia do not quite reach the edge of the sori. Individual sporangia are easily visible around the edge of each sorus. Sori with hood-like indusia.
What is Stomium and its function?
stomium An area of thin-walled cells in a sporangium or pollen sac that breaks to release the spores or pollen grains when the surrounding tissue dries. A Dictionary of Plant Sciences.
What is the Endothecium?
Definition of endothecium : the inner lining of a mature anther.