2 FUNGUS-FLORA. 



the hypha consists of a row of superposed cells. In numerous 

 species the hyphae form a loose, yielding structure, as in the 

 common mushroom, where they are arranged in a more or 

 less parallel manner in the stem or stipe, or intricately inter- 

 woven, as in the cap or pileus. In perennial species, on the 

 other hand, the hyphae are compacted to form a dense, 

 elastic, corky tissue ; or, in some species of Polyporus, the 

 substance becomes dark-coloured and as hard as wood. The 

 loose, floccose hyphae forming the vegetative portion of the 

 fungus is called the mycelium, or spawn. In many species 

 certain of the hyphae become differentiated into laticiferous 

 hyphae, and contain a dense, granular liquid called latex, or 

 ' milk,' as usually described in systematic works ; such cells 

 are exceedingly abundant in the genus Lactarius, and con- 

 stitute one of its specific characters, the ' milk,' or latex, 

 escaping in drops when the tissue is broken. Laticiferous 

 cells are also present in many other genera. 



The Fungi are considered as having descended from the 

 algae, the initial phase of departure being the suppression of 

 chlorophyll, after which they gradually adopted an aerial 

 mode of life; and at the present day we recognise two 

 primary lines of departure and specialisation, the Ascomycetes 

 and the Basidiomycetes. The first-named group is oldest in 

 point of time, and, as would be expected, is structurally most 

 in touch with the algae, especially the lower or algal-like 

 forms, such as Pythium, Saprolegnia, &c., which differ from 

 certain algae, as Vaucheria, more especially in the absence of 

 chlorophyll, in other respects the general structure is almost 

 identical; such fungi are in many instances aquatic, and 

 possess sexual organs of functional value, an antheridium, or 

 fertilising body male and a large cell, or oogonium 

 female the contents of which, after fertilisation, become 

 capable of reproducing the species ; the fertilised bodies con- 

 tained within the oogonium, or mother-cell, are called 

 oospores, and the leading idea of the Ascomycetes is that of 

 producing the reproductive bodies or spores in a mother-cell, 

 where they remain till mature. As the evolution of the 

 Ascomycetes proceeds, the sexual organs are gradually sup- 

 pressed, until eventually the spores are produced in a mother- 

 cell or ascus without the intervention of any sexual process. 

 Along with the above mode of reproduction, a second or 



