The Collaborative International Dictionary of English v.0.48:

Fungi \Fun"gi\ (f[u^]n"j[imac]), n. pl.; sing. fungus. (Biol.)
   A group of thallophytic plant-like organisms of low
   organization, destitute of chlorophyll, in which reproduction
   is mainly accomplished by means of asexual spores, which are
   produced in a great variety of ways, though sexual
   reproduction is known to occur in certain Phycomycetes, or
   so-called algal fungi. They include the molds, mildews,
   rusts, smuts, mushrooms, toadstools, puff balls, and the
   allies of each. In the two-kingdom classification system they
   were classed with the plants, but in the modern five-kingdom
   classification, they are not classed as plants, but are
   classed in their own separate kingdom fungi, which includes
   the phyla Zygomycota (including simple fungi such as bread
   molds), Ascomycota (including the yeasts), Basidiomycota
   (including the mushrooms, smuts, and rusts), and
   Deuteromycota (the fungi imperfecti). Some of the forms,
   such as the yeasts, appear as single-celled microorganisms,
   but all of the fungi are are eukaryotic, thus distinguishing
   them from the prokaryotic microorganisms of the kingdon
   Monera.
   [Webster 1913 Suppl. +PJC]

   Note: The Fungi appear to have originated by degeneration
         from various alg[ae], losing their chlorophyll on
         assuming a parasitic or saprophytic life. In an earlier
         classification they were divided into the subclasses
         Phycomycetes, the lower or algal fungi; the
         Mesomycetes, or intermediate fungi; and the
         Mycomycetes, or the higher fungi; by others into the
         Phycomycetes; the Ascomycetes, or sac-spore fungi;
         and the Basidiomycetes, or basidial-spore fungi.
         [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

Mesomycetes \Mes`o*my*ce"tes\, n. pl. [NL.; meso- + mycetes.]
   (Bot.)
   One of the three classes into which the fungi are divided in
   Brefeld's classification. -- Mes`o*my*ce"tous, a.
   [Webster 1913 Suppl.]