. Fig. 189. — Polyporus sulphureus showing effect upon wood of oak tree. After von Schrenk. The upper surface is very hard and bears fine, irregular fissures parallel to the edge. When mature, the upper surface is red-brown. The pores are barely visible without a hand lens. Soft-rot ^^^ {Polyporus obtusus Berk.). — The black oaks

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Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1921