General Information: This fungus may also grow on old sawdust heaps, a habitat which is often very worth while examining in detail by the interested amateur during wet seasons. In summer sawdust heaps dry out but after a good soaking, which, of course, can be applied artificially by frequent watering with a hose or watering-can, many interesting fungi develop. On sawdust heaps containing conifer debris a larger species with black or dark brown edge to the gills is found—P. atromarginatus Kühner.
The peculiar pointed cystidia found on the gill-edge and on the gill-face of P. cervinus were thought by some early mycologists to stop mites and insect larvae from crawling up between the gills and damaging the developing spores. There is no evidence that this actually takes place in nature; the real purpose of these obscure structures is unknown and has been little studied.
Illustrations: Hvass 127; LH 121; NB 1351; WD 502.
Plate 15. Fleshy fungi: Spores pinkish and borne on gills
![[Larger illustration]](#467779198995390083_illo071lg.png.id-4669155318750459981.wrap-0.html.html){kind=link}
Gymnopilus penetrans (Fries) Murrill
Cap: width 20-50 mm. Stem: width 4-7 mm; length 20-50 mm.
Description:
Cap: convex then becoming flattened at maturity, dry, slightly scaly, golden tawny, or rusty yellow and when young with the remnants of a rapidly disappearing yellow cortina hanging from the margin.