530 



Tniv Ei.M Pleurotus (Ediblk) 

 Plciirotiis iiUuarius Bull. 



The elm Pleurotus is so called because it is often found growings 

 (Vii elm trees and logs. It is not confined to elms, however, but is found 

 on many kinds of trees. At Urbana it is much more common on box- 

 elder (ash-leaved maple) than on elm. It grows from the sides of 

 trees, where branches have been broken off or the trees have been 

 wounded from some other cause, from September until winter. It is 

 more likely to be found in or near cities than in the country. This is 

 a large plant and is easily distinguished from the oyster mushroom by 

 its long stem, which is usually attached near the center, and by the 

 gills, which are rounded or notched at the end next to the stem instead 

 of decurrent. The plants usually grow singly, but several may be 

 found on the same tree and sometimes they are more or less clustered. 



The cap is 5 to 15 cm. (2 to 6 inches) broad, fleshy but firm and 

 compact, at first convex and with the margin incurved, then flat or 

 nearly so, always horizontal no matter what the position of the stem 

 may be, smooth but often with the surface more or less cracked, white 

 or whitish and sometimes tinged with red, yellow, or brown, and 

 usually becoming darker and shining when old. The flesh is thick, 

 firm, rather tough, and pure white. 



The gills are broad. l)ut narrower at each end, notched or rounded 

 at the inner end, attached to the stem l)y the upper angle (adnexed), 

 rather close together, white or whitish. The spores are white. 



The stem is 2.5 to 10 cm. ( i to 4 inches) long, stout, solid, straight 

 or curved according to the place of growth, more or less eccentric but 

 often very nearly, if not quite, central, often somev/hat thickened at 

 the base, smooth, or somewhat downy with short hairs, especially at 

 the base. The stem is white and there is no ring and no volva. 



The elm Pleurotus has been known as an edible mushroom for a 

 long time and is considered excellent l)v many people. It does not 

 become infested with insects nearly so quickly as the oyster mushroom, 

 and it can easily be dried and kept for winter use. Like all tree mush- 

 rooms it should 1)e eaten when voung, since old specimens are rather 

 tough. 



Although this mushroom grows on living trees, it seems to feed 

 only on the dead portions of the bark and wood, and its growth ap- 

 pears to do no harm to the tree. 



Collected in Champaign county. 



