Phylum: Basidiomycota
Basidiomycota are the second largest group of fungi,
approximately 3,000 species. Including organisms commonly known as mushrooms,
bracket or shelf fungi, earthstars, bird s nest fungi, rusts, smuts, and
puffballs. Basidiomycota are characterized primarily by the fact that they
produce spores on a structure called a basidium. The basidium is a club shaped
terminal cell within which karyogamy and meiosis occurs while the basidiospores
are produced externally. Typically, four basidiospores are produced on each
basidium. The morphology of the basidium is variable and consider once of the
basis for classifying the fungi to classes, The basidiospores are attached
(usually) to the basidium on special stalks called sterigmata. In most species
basidia are formed in a specialized layer called the hymenium.
Basidiomycota fungi exist, for most of their lives,
in the form of a simple mycelium consist of branched septate hyphae each septum
have a central barrel-shaped structure called a dolipore covered on
both sides by a cap of membrane called a parenthesome . They initially begin life as a hypha with
one nucleus per cell. When two hyphae from the same species meet and are
compatible, they will join and the two separate nuclei take up residence within
the fused cell. The hypha continues to grow and a special mechanism "clump-connection" makes it possible for the two
different nuclei to be passed from cell to cell (when a binucleat cell is ready
to divide, a short branched arise between the two nuclei and begins to form a
hook). Basidiomycetes may live for many years in this dikaryotic mycelial
state. When environmental conditions are favourable, the