The recent observations and exceedingly ingenious experiments of Falck have shown that the sporophores of the Basidiomycetesespecially the large sporophores of such forms as Boletus, Polyporus- contain quantities of reserve combustible material which are burnt up by the active metabolism occurring when the fruit-body is ripe.
Ar- millaria melleus and Polyporus annosus are examples of parasitic forms which attack and destroy living trees, while Merulius lacryg s !
Such aggregations of hyphae frequently become knotted up into dense masses of interwoven and closely packed hyphae, varying in size from that of a pin's head or a pea (Peziza, Coprinus) to that of a man's fist or head, and weighing io to 25 lb or more (Polyporus Mylittae, P. tumulosus, Lentinus Woermanni, P. Sapurema, &c.).
In many cases the swollen cell-walls serve as reserves, and sometimes the substance is so thickly deposited in strata as to obliterate the lumen, and the hyphae become nodular (Polyporus sacer, P. rhinoceros, Lentinus Woermanni).
In Germany a fungus (Polyporus Laricis) grows on the roots and stems of decaying larches, which was formerly in esteem as a drastic purgative.