136 INTRODUCTION TO THE STUDY OF FUNGI 



sented by a folded membrane, in the form of parallel plates or 

 gills. Instead thereof the gills are replaced by parallel tubes, 

 more or less adnate to each other, presenting a surface 

 punctured with an infinity of minute pores, sometimes as small 

 as if pricked with a pin. The membrane which lines the sides 

 of these tubes or pores is the hymenium, so that the spores 

 are produced within the tubes and not so fully exposed as in 

 the Affaricincae. If we take as a type one of the species of 

 the soft and fleshy genus Boletus, we shall see that in some re- 

 spects it resembles the ordinary mushroom, and at the same time 

 detect its more prominent differences (Fig. 51). In the presence 

 of mycelium, stem, and cap the Boletus agrees with the Agarics, 

 but the section will show the parallel tubes replacing the gills. 

 But this is not so complete a type of 

 the whole Pohjporei as was the Agaric 

 of the Agaricini. In the first place 

 the stem is often absent and the cap 

 or pileus sessile, attached by the 

 margin. And, in the second place, 

 the pileus, or what corresponds to the 

 pileus, adheres to the matrix by its 

 whole upper surface, and only the 

 hymenium, or pore -bearing surface, is 

 exposed. This resupinate condition is 

 Fig. 5i.-5o^d«,9, with section ^^^.y common, SO that the essential 



and spores. •' 



character is a porous hymenium, seated 

 upon the least possible development of a pileus. And yet, 

 as far as practicable, the hymenium is inferior, or turned away 

 from the light. We are prepared, then, to meet with a greater 

 variety of form than in the Agaricini, as well as greater ex- 

 tremes of texture. 



The nearest approach to Agaricini in habit is to be found 

 in the four genera Boletus, Strohilomyces, Boleti^ius, and Gyrodon. 

 All these were, in their earlier history, associated together as 

 Boletus, but at length came to be dissevered and recognised as 

 distinct genera. Strohilomyces is Boletus with a scaly pileus ; 

 Boletinus is Boletus with short, large, radiating pores; and 

 Gyrodon is Boletus with elongated, sinuate, irregular pores. 

 All of these are fleshy but firm, soon putrescent, but mostly 



