Minnesota Plant Diseases. 267 



soft wood timbers wherever they are .placed in conditions favor- 

 able to the fungus. The fruiting body is either a flat prostrate 

 one or may become a low shelf. It is seldom large and does 

 not usually exceed a few inches in diameter. The exposed sur- 

 face is covered with gills which often radiate from the center in 

 the prostrate forms. The fruiting bodies are tough-leathery to 

 woody and dark-yellow- to red-brown in color. The top of the 

 cap is somewhat hairy when young, becoming more or less 

 smooth when old. The gills are rather thick. 



The scaly Lentinus rot (Lentinus lepideus Fr.). This is a 

 very familiar gill fungus which inhabits almost all kinds of soft 

 needle-leaved tree timbers. It is, as far as is known at present, 

 a saprophyte. It is very frequently met with on fence rails and 

 posts, dead and down tamarack and other kinds of coniferous 

 wood, as well as on wood partially submerged in the soil or 

 water. The fruiting body is a stalked form with a central stem 

 and is very tough-fleshy. The cap is two to< three inches or 

 more across and is at first pale yellow. Later, black scales de- 

 velop on the upper surface. The flesh of the cap is white. 

 The gills are slightly wavy, running down the stem for a short 

 distance and the margins are irregularly toothed, a character by 

 which this fungus and its close relatives can readily be distin- 

 guished from other gill fungi. The gills are white, tinged with 

 yellow. The stem is one inch or more in length and usually ta- 

 pers toward the base, is hard, pale in color and has scales similar 

 to those of the cap. The fruiting bodies sometimes grow in 

 clusters. 



The green cup-fungus rot [Chlorosplenium aeruginosum 

 (Oedcr.) DeN.']. On various kinds of woods, including bal- 

 sam fir and birch, grows a fungus with a remarkable habit. 

 The mycelium penetrates deeply, being especially prominent 

 in the spring wood. It colors the wood a very beautiful, deep 

 verdigris green, varying in shade in the different parts. It is 

 more abundant in the summer wood, thus accentuating the 

 grain. The rot works very slowly. Wood, so colored by artificial 

 infection, is used in the arts in the manufacture of Tunbridge 

 ware. It is also used for the extraction of the pigment which 

 resides both in the mycelium and the adjacent walls. The fruit- 

 ing body is a small stalked cup which at first sight looks much 



