74 MANUAL OP BOTANY 



gives rise to them, and remain dormant for a longer or shorter 

 period, ultimately putting out hyphse like those of the original 

 mycelium. 



The fungi have been classified in various ways by different 

 writers. The system which is now usually adopted divides them 

 into six groups as under ; — 



1. Schizomycetes, including those bodies commonly spoken of as 



microbes, or bacteria. They are sometimes unicellular, 

 sometimes filamentous and composed of chains of cells. 

 They have no sexual reproduction. 



2. Myxomycetes. The body of the fungus is a Plasmodium or 



aggregation of amoeboid cells with no cell-wall. They 

 produce spores, but have no sexual reproduction. 



3. Phycomycetes. These have usually a mycelium composed of 



a much-branched coenocyte with no septa. They are often 

 erroneously described as unicellular, a condition which, 

 however, does occur in some cases. They reproduce 

 sexually and asexually, zoospores and ordinary non-motile 

 spores occurring in different orders. The sexual reproduc- 

 tion is a process of conjugation or fertilisation, leadiag to 

 the recognition of two groups accordingly, -the Zygomycetes 

 and the Oomycetes. In the former the zygote is a zygo- 

 spore, in the latter an oospore. 



4. Ascomycetes. The coenocytic structure is found in this 



group also, but the whole plant is usually not a single 

 ccenocyte, but incompletely septated, forming a number of 

 them. The female organ is a carpogonium, containing no 

 differentiated gamete ; the sporophyte is inconspicuous, but 

 represented by the so-called fructification. 



a. ^cidiomycetes. The mycelium has the same structure as in 

 the last group. There is no sexual reproduction known. 

 Several kinds of spore are borne. There is an elaborate 

 structure produced called an mcidium, which may possibly 

 represent the sporophyte, but the homologies are doubtful. 



6. Basidiomycetes. The mycelium is much like those of the last 

 two groups. No sexual reproduction is known. The 

 mycelium produces a massive structure, on certain parts of 

 which the spores are produced by abstriction from special 

 cells, known as hasidia. 



Sub-Class I. — Schizomycetes. 

 The members of this group are very small, and almost struc- 

 tureless. The unicellular forms have various shapes, some being 



