88 FUNGI. 



thick, brown cell-walls, and contents rich in fats (resting conidia), 

 can withstand unfavourable external conditions for a much longer 

 period than conidia with thin walls and poor in contents. 



The SPORANGIA arise either from the ordinary cells of the 

 mycelium (Protomyces\ or are borne on special hyphre. They are 

 generally spherical (Mucor, Fig. 80 ; Saprolegniacese), egg-, pear-, 

 or club-shaped (Ascoriiycetes), more rarely they are cylindrical or 

 spindle-shaped. While among the Phycornycetes the size, form, 

 and number of spores are indefinite in each species, in the Ascomy- 

 cetes the sporangia (asci) have a definite size, form, and number 

 of spores. The spores of the Ascomycetes are known as asco- 

 spores. 



The sporangio-fructification is found under three main forms. 



1. FREE SPORANGIOPHORES which are either single (Mucor, Fig. 

 78), or branched (Thamnidium). 



2. SPORANGIAL-LAYERS. These are produced by a number of 

 sessile or shortly-stalked sporangia, being formed close together 

 like a palisade (Taphrina, Fig. 105). 



3. SPORANGIOCARPS. These consist usually of many sporangia 

 enclosed in a covering, they are found only in the Carpoasci, and 

 are also known as ascocarps. The parts of an ascocarp are the 

 covering (peridiutn), and the hymenium, which is in contact with 

 the inner wall of the peridium, and is generally made up of asci, 

 and sterile, slender hyphje. The latter either penetrate between 

 the asci and are branched and multicellular (paraphyses, Figs. 

 103 d, 123, 125, 129), or clothe those parts of the inner wall which 

 bear no asci (Periphyses ; among many peronocarpic Ascomycetes, 

 e.g. Chwfomium, Sordaria, Stictosphce.ra lioffmanni). The ascocarps 

 are produced directly from the mycelium, or from a stroma, that 

 is a vegetative body of various forms, in which they may be 

 embedded (Figs. 116 B, C). 



Among the conidio-fructifications there are, in the same way, 

 three divisions. 



1. FREE CONIDIOPHORES (Fig. 109). The form of the conidiophores, 

 the shape, and number of its spores are various. Iii the most 

 highly developed Fungi, the Basidiomycetes, there are, however, 

 special more highly developed conidiophores, the basidia, which 

 have a definite form ana spores of a definite shape and number. 

 The conidia borne on basidia are called busidiozpores. 



2. CONIDIAL-LAYERS. (a) The SIMPLEST case of this is found 

 when the conidiophores arise directly from the mycelium, parallel 



