A sorus (: sori) is a cluster of sporangium (structures producing and containing ) in and fungi. A coenosorus (: coenosori) is a compound sorus composed of multiple, fused sori.
Etymology
This
Neo-Latin word comes from the
Ancient Greek word (), meaning "stack, pile, heap, etc.".
Structure
In
and other fungi, the sorus is surrounded by an external layer. In some red algae, it may take the form of depression into the
thallus.
In ferns, the sori form a yellowish or brownish mass on the edge or underside of a fertile frond. In some species, they are protected during development by a scale or film of tissue called the indusium (: indusia), which forms an umbrella-like cover.
Life cycle significance
Sori occur on the
sporophyte generation, the sporangia within producing
haploid meio
. As the sporangia mature, the indusium shrivels so that spore release is unimpeded. The sporangia then burst and release the spores.
As an aid to identification
The shape, arrangement, and location of the sori are often valuable clues in the identification of fern
taxa. Sori may be circular or linear. They may be arranged in rows, either parallel or oblique to the costa, or randomly. Their location may be marginal or set away from the margin on the frond lamina. The presence or absence of indusium is also used to identify fern taxa.
== Gallery ==
See also
References and external links
