82 DISEASES OF DECIDUOUS FOREST TREES. 



Page. 



Plants, epiphytic, injuries to trees 17 



parasitic, causing diseases of trees 14-18 



Platanus occidentalis. See Sycamore. 



Plates, description 74 



Poles, broadleaf, decay caused by Polystictus versicolor, description 53-56 



Polyporus betulinus, cause of birch sap-rot, description 51-52 



sporophores, description t . 51, 74 



obtusus, cause of oak soft-rot, description 41-42 



sporophores, characteristics 41 



squamosus, cause of white-rot, description 48-49 



sulphureus, description, growth, habits, and injury to trees 37-39, 74 



edible qualities 37 



preventive measures 38-39 



Polystictus pergamenus, cause of sap-rot in dead wood, description 56-58 



decay similar to that caused by Polystictus versicolor. . 58 



species, resembling P. versicolor and P. pergamenus 61 



versicolor, cause of sap-rot in dead wood, progress of decay 53-56 



soft heart-rot of catalpa, description, growth, 



and prevention 47^18 



distribution 53 



sporophores, description and growth in cut timber 53-56 



Poplar, leaf-rust fungus injury 19 



tulip, sap-rot, occurrence 57 



susceptibility to injury by sulphur gas and ground water 11, 12, 13 



white heart-rot, susceptibility 30 



Populus balsamifera. See Balm of Gilead. 

 deltoides. See Cottonwood, 

 tremuloides. See Aspen. 

 Post oak. See Oak, post. 



Posts, broadleaf, decay caused by Polystictus versicolor, description 53-56 



Preservation, wood, by chemicals to prevent decay 66, 67 



Prionoxystus robiniae, oak-boring insect preceding fungus of soft-rot 41 



Prosopis juliflora. See Mesquite. 



Puccinia fraxinata, cause of leaf-rust of ash 19 



Punks, fungi injurious to forest trees, description 25-61 



Pyrenomycetes fungi, injury to forest trees, mode of attack 21 



Pyrus communis. See Pear. 



malus. See Apple. 

 Quercus spp. See Oak. 



Ramalina reticulata, injury to trees 18 



Red gum. See Gum, red. 



heart-rot. See Rot, heart, red. 



Rhizomorphs, honey mushroom, description and growth 23-24 



Rhytisma acerinum, cause of tar-spot disease of maple 19 



Robinia pseudacacia. See Locust. 



Root-rots, causes, symptoms, and destruction of trees . 22-24 



Roots, tree, injury by gas through poisoned soil 12 



Rot, heart, cause, description, and injury to trees 42-44 



oaks, caused by Fomes everhartii, description 48 



red, birch, cause and description 47 



caused by Polyporus sulphureus 37-39 



soft, catalpa, cause, description, and prevention. . . '. 47-48 



149 



