CHAPTER XLIX. 



FUNGI {continued). 



BASIDIOMYOETES. 



I. The Basidiomycetes are an extensive class of the Higher 

 Fungi, the species of which are very variable in size and shape, 

 but all characterised by the production of a more or less dis- 

 tinct form of conidiophore, termed a basidium, upon which are 

 borne a small and often very definite number of simple conidia 

 designated basidiospores. 



Sexual reproduction is quite unknown, and endospores within 

 sporangia are also absent. 



Two sub-classes are recognised, namely, (i) the Hemibasidii, 

 to which belong the ' smut '-fungi so destructive to cereals ; 

 and (2), the Eubasidii, which includes the parasitic 'rust '-fungi 

 and also a vast group of higher forms, mainly saprophytic, 

 of which the mushroom, toadstools, and puff-ball fungi are 

 examples. 



Sub-class I. — Hemibasidii. 



2. The Hemibasidii are typical parasites which chiefly attack 

 flowering plants and especially the cereals and grasses. Their 

 mycelia are usually very slender at first, but after a time certain 

 portions, or the whole of their hyphse, swell and become 

 divided up in the production of vast numbers of dark-coloured 

 chlamydospores which in some species are only produced within 

 the tissues of the host at very definite points, such as the ovaries, 

 nodes of the stem, and certain limited areas of the leaves. 



The chlamydospores very frequently rupture the tissues in 

 which they are produced, and appear on the outside as a black 

 powder resembling soot. 



