se ut. I CRYPTOGAMS 343 



fructifications in the form of asci or basidia, there occur also acces- 

 sory fructifications in which conidia of various forms are produced. 

 Both series also exhibit an increasing complication in the arrange- 

 ment of their respective asci or basidia. While in the simpler 

 groups the asci or basidia arise free on the hyphse, in the more highly 

 developed Ascomycetes and Basidiomycetes more or less complicated 

 fructifications are produced, ascns fructifications in the former, basidia 

 fructifications in the latter. In both of these last two groups fructi- 

 fications, externally very similar and of a tuberous or toadstool-like 

 shape, are often formed. The asci and also the basidia are disposed 

 in a definite layer or hymenitjm, which is in part composed of sterile, 

 club-shaped cells termed paraphyses (Fig. 290, p. 368). The 

 hy menial layer covers the walls of the external cavities of the fructi- 

 fication or is exposed on its surface at definite points. 



In addition to the sporangia and conidia there occurs also a 

 third form of spore -formation, the so-called chlamydospores (en- 

 cased spores). These spores may be produced by the Phycomycetes as 

 well as by the higher Fungi. The chlamydospores are usually formed 

 in rows on hyphse ; they are regarded as rudiments of sporangia 

 or of conidiophores which, interrupted in their development, have 

 assumed the form of spores, and like them serve the purpose of 

 asexual reproduction (Fig. 272, p. 350). On germination they usually 

 develop into either sporangia or conidiophores. The Hyphomycetes 

 may be classified according to the following system of Brefeld, 

 established in conformity with the preceding principles. 



A. Algal Fungi, Phycomycetes, with unicellular mycelium and sexual 



reproduction. 



Sub-Class 1. Oomycetes. Sub-Class 2. Zygomycetes. 



With oogania and antheridia ; Zygospores formed ; asexual 



asexual reproduction usually by reproduction by means of spor- 



means of swarm-spores. angia or conidia. 



B. Higher Fungi, hyphse septate and without sexuality. 



Series 1. Sporangia-bearing Series 2. Conidia-bearing 



Fungi. Fungi. 



With sporangia, in addition to conidia. With conidia ; no sporangia. 



Sub-Class 3. Hemiasci. Sub-Class 5. Hemibasidii. 



Sporangia resembling asci. Conidiophores resembling basidia. 



Sub-Class 4. Ascomycetes. Sub-Class 6. Basidiomycetes. 



Sporangia developed as true Conidiophores developed as 



asci. true basidia. 



The Hemiasci and Hemibasidii were classified as Mesomycetes by Brefeld ; the 

 Ascomycetes and Basidiomycetes as Mycomycetes. 



