VI Journal of Agricultural Research voi. ui 



Heart-Rot of Oaks and Poplars Caused by Polyporus 

 Dryophilus 



Paee. 



Plate VIII. Fig. i. — Quercus alba: Crescent-shaped "soak," the initial stage 

 of the piped rot produced by Polyporus dryophilus; from Arkansas. Fig. 

 2. — Quercus alba: A radial view of the rot in a limb, showing delignification; 

 from Arkansas. Fig. 3. — Quercus oblongifolia: A radial view of rot, showing 

 delignification; from Arizona. Fig. 4. — Quercus alba: A final stage of the 

 rot, radial view, with more complete delignification; from Arkansas. 

 Fig. 5. — Quercus alba: A tangential view of the rot, showing delignification 

 in pockets; from Arkansas. Fig. 6. — Querents alba: An end view showing 

 a cross section from the same tree as the preceding: from Arkansas. Fig. 

 7. — Quercus sp.: A section of oak from Von Tubeuf, sent to the jmiior 

 writer as a specimen of the rot caused by Polyporus dryadeus in Europe. 

 Fig. 8. — Quercus sp.: The reverse side of the specimen shown in the pre- 

 ceding. Fig. 9. — Quercus sp.: A section of oak from Europe, obtained by 

 Von Schrenk, with a piped rot similar to that of Polyporus dryophilus . ... 78 



Plate IX. Fig. i. — A sporophore of Polyporus dryophilus, tuberous form on 

 Quercus gambelii; from Arizona. Fig. 2. — Sectional view of a sporophore 

 of Polyporus dryophilus on Quercus gambelii, showing the hard granular 

 core with whitish mycelial strands; also the pore layer; from New Mexico. 

 Fig. 3. — A sporophore of Polyporus dryophilus on Quercus californica, show- 

 ing the upper siu^ace with a faint zonation; from California. Fig. 4. — A 

 section through a sporophore of Polyporus dryophilus on Quercus garryana, 

 showing the structure of the hard granular core ; from California. Fig. 5. — 

 A front view, showing the margin of the same sporophore as in figure 3, 

 representing the ungulate form. Fig. 6. — A view of the pore surface of 

 an applanate sporophore of Polyporus dryophilus on Quercus alba; from 

 Arkansas 78 



Plate X. Fig. i. — A sporophore of Polyporus dryophilus, front view showing 

 the margin, on Populus iremuloides; from Colorado. Fig. 2. — ^A second 

 sporophore from the same tree as figiu-e i, showing an imbricated form. 

 Fig. 3. — A view of the upper surface of a sporophore of Polyporus rheades on 

 Populus tremula; from Stockholm, Sweden. Fig. 4.^A sectional view of 

 a sporophore of Polyporus corruscans on Quercus; from Upsala, Sweden. 

 Fig. 5. — A side view of an imbricate sporophore of Polyporus dryophilus, 

 applanate form on Populus Iremuloides; from Colorado. Fig. 6. — A sec- 

 tional view of the same sporophore as in the preceding figure, showing the 

 hard granular core and whitish mycelial strands. Fig. 7. — A view of the 

 upper surface of an applanate sporophore of Polyporus dryophilus on Quercus 

 alba; from Arkansas. Fig. 8. — The pore surface of a sporophore of Poly- 

 porus dryophilus on Populus iremuloides; from Colorado 78 



A Fungous Disease of Hemp 



Plate XI. A hemp plant, showing upper branches attacked by tlie fimgous 



Botryosphaeria marconii 84 



Natural Revegetation of Range Lands Based upon Growth 

 Requirements and Life History op the Vegetation 



Plate XII. Fig. i. — View of the lower grazing lands in the Wallowa National 

 Forest. Fig. 2. — Characteristic open stand of western yellow pine and 

 dense cover of herbaceous vegetation, mainly pine-grass (Calamagrostis 

 pubescetis), Wallowa National Forest. Transition zone (yellow-pine asso- 

 ciation). Fig. 3. — A burned-over area of lodgepole pine, with character- 

 istic dense sapling stand 148 



