446 



COMPARATIVE MORPHOLOGY OF FUNGI 



timber decay, Brefeld (1889) reported that the hyphae first form a felt 

 with groups of basidia which gradually become more numerous and 

 form compact hymenia. Later, portions of the hymenophore grow 

 rapidly, separating the hymenium into circular discrete areas. The 

 growing edges remain sterile, although the hymenium continues to form 

 on the walls of the developing tubes. On the other hand, Burt (1917) 

 states that he has never found basidia in Porta until the pores are fully 

 formed. The difference in many cases is dependent on subjective 

 measurements, particularly of herbarium material. 



Fig. 287. — Fomes annosus. 1. Exterior of normal conidiophore. 2. Section of same. 

 3 to 5. Small branched conidiophores with heads of few spores in 5, partially reduced to four. 

 6. Single, basidium-like conidiophore heads with four spores each. 7. Four-spored basidia 

 surrounded by paraphyses. (1 to 6 X 300; 7 X 350; after Brefeld, 1899.) 



Fomes annosus (Trametes radiciperda) is very destructive to pine. 

 The hyphae penetrate the roots, mount the trunk and cause there a red 

 rot of the wood. Fructifications arise at the roots and are mainly resupi- 

 nate. Every year is formed a new layer of pores which largely covers 

 the older layer like a membrane. There have been reported (Brefeld, 

 1889) conidia similar to those of Pustularia vesiculosa and Corticium 

 effuscatum (Fig. 287). The hyphal ends swell to knobs and cut off numer- 

 ous hyaline conidia on very fine sterigmata of variable length. These 

 conidia can develop to new mycelia while still sessile on the heads. In 

 exceptional cases, there occur little heads with few spores, which are then 

 similar to four-spored basidia and were considered by Brefeld as the 



