THE Fungi are enormously numerous. No less than 2,000 of the highest and most conspicuous of these plants have been figured; many more have been described; multitudes of those inhabiting the torrid zone are unknown; and the microscopic and parasitic tribes are innumerable. Though with a few exceptions entirely formed of cellular tissue, the fungi resemble animals in respiration and chemical constitution. They contain more azote than any other of the Cryptogamia, and obtain it chiefly from their food, which consists of animal and vegetable substances alive, dead, or decomposed. They inhale oxygen, and exhale carbonic acid gas, so that they never form true chlorophyll. No plants are more dependent on heat and moisture; many perform all the functions of life and reproduction independently of light, preferring dark and shady places to sunshine. The Fungi form two principal groups, distinguished by their mode of fructification. In the higher group, _Sporiferi_, the fungus produces naked spores either single or compound, by means of which it may be multiplied. In the lower group, _Sporidiiferi_, the fructification consists of sporidia, enclosed in a distinct sac. The Sporiferi include the following orders, Hymenomycetes, Gasteromycetes, Coniomycetes, and Hyphomycetes. The Sporidiiferi include the Ascomycetes and the Physomycetes. These various groups we may now proceed to examine. The most important family of Fungi is, without question, that of the HYMENOMYCETES, the species of which far excel all others in their richness of colouring, and beauty of form. In this group the hymenium is free and mostly exposed. It comprises six orders, of which the Agaricini hold the first place. The genus Agaricus alone comprises 1,000 distinct species, which assume as many different forms and colours, with only slight modifications of substance, and it surpasses in number of species all the other generic groups known.