[Vol. 2 



676 ANNALS OP THE MISSOURI BOTANICAL GARDEN 



Hyphal characters. — The characters of the hyphae that 

 make up the subhymenial tissue and the tissue of the trama 

 of the pileus have never been used in the classification of the 

 Polyporaceae. While the size of the hyphae may depend to 

 a considerable degree on the food supply of the plant, yet in 

 examining a large number of species the writer has found that 

 some are characterized by hyphae two to three times as large 

 as in most species. These cases have been thoroughly investi- 

 gated as far as herbarium material would permit and as all 

 specimens have showed the character about equally well, it 

 has been taken as a means of identifying the species in which 

 it has occurred. The writer knows of no factor or combina- 

 tion of factors that would be operative on a large number of 

 individuals from widely separated localities and in the case 

 of but a limited number of species. If it be dependent on 

 nutrition, then the species possessing this character are so 

 constantly associated with that kind of nutrition that the 

 character is as constant a one as can be obtained. The same 

 is true of the unbranched hyphae of the context of Poly poms 



albellus. 



Incrustation of the hyphae has never been observed in the 

 pileate Polyporaceae, though it is a well-marked character in 

 the species of certain groups of resupinate fungi. 



METHODS EMPLOYED 



A few words may not be amiss here concerning the methods 

 employed by the writer in obtaining these microscopic char- 

 acters. In general the method is that already described in a 

 previous number of this journal. 1 



Obtaining spore prints. — In the case of fresh specimens 

 just brought into the laboratory from the field, spore prints 

 are very easily obtained by placing the specimens on a glass 

 slide in such a manner that the tubes are in a perpendicular 

 position so that the spores do not lodge on the sides of the 

 tubes when they are liberated from the basidia. The slide 

 with the fungus in position should be either wrapped in waxed 

 paper or left over night or for several hours in the collecting 



1 Burt, E. A. loc. cit. 



