MIDDLETON FUNGI. — GiATES. 117 



basidimu, and its basidiospores have been regarded as sexual. 

 Strasburger objects to this view, regarding the process as merely 

 a nutritive one, stiuiulating development. He holds that a 

 second essential of fertili/^ation is the union of diverse ancestral 

 qualities, and this cannot take place between nuclei so nearly 

 related. 



Thus the question of the origin and relationships of the 

 Bisidiomycetes still remains obscure owing to their having lost 

 a sexual method of reproduction, although in the structure of 

 the fructification, (i. e., the part bearing asexual spores), they 

 are by far the most highly developed group of the fungi. 



Brefeld and his school regard the whole class of fungi as a 

 single one, deny the sexuality of the Ascomycetes, and derive 

 both Ascomycetes and Basidiomycetes from the Phycomycetes. 

 Recent investigations are, however, opposed to these views, as it 

 has been shown that the formation of spores in the ascus by 

 free cell formation is essentially ditlerent from the method of 

 spore formation in the Ph3^comycetes. 



Economically, two of the most important orders of the 

 Basidiomycetes are the Ustilagineaj and Uredinea3. These are 

 the cause of the destructive "smuts "and " rusts " on cereals; 

 but they cannot be discussed further here, although their life 

 history is of the greatest interest. 



The group of Basidiomycetes which comprises the so-called 

 higher fungi, our mushrooms and toadstools, is the Hymsnomy- 

 cefes. They are both parasitic and saprophytic, and their 

 mycelium is widely spread in dead and living plants and in 

 soils. 



The leaf mould of our forests is permeated with it; and 

 every fallen log is preyed upon by series of fungi in addition to 

 the action of bacteria and weathering processes, until it is finally 

 reduced to a shapeless mass and mingled with the soil, there to 

 add its share to the nutritive material upon which the saprophy- 

 tic fungi in the soil subsist. 



The spores of parasitic fungi, or " wound parasites," as they 

 are often called, when blown by the wind alight upon a spot on 



Proc. & Trans. N. S. Inst. Sci., Vol. XI. Trans.-I. 



