. Botany for agricultural students. Plants. Fig. 322.— Pus- tules on the bark of a Chestnut caused by the Chestnut Blight Fungus. PVom Bullelin 380, U. S. Dept. Agri- culture, Fig. 323. — Powdery Mildew on an Apple leaf. The light areas are due to the presence of many superficial hyphae. From Bulletin 185, Maine Agr. Exp. Sta. produced {Fig. 322). The summer spores are extruded in threads and spread the disease to other trees. In autumn these same pustules develop deeply buried perithecia in Avhich the ascospores (winter spores) develop. The ascospores germinate the next spring and when

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. Botany for agricultural students. Plants. Fig. 322.— Pus- tules on the bark of a Chestnut caused by the Chestnut Blight Fungus. PVom Bullelin 380, U. S. Dept. Agri- culture, Fig. 323. — Powdery Mildew on an Apple leaf. The light areas are due to the presence of many superficial hyphae. From Bulletin 185, Maine Agr. Exp. Sta. produced {Fig. 322). The summer spores are extruded in threads and spread the disease to other trees. In autumn these same pustules develop deeply buried perithecia in Avhich the ascospores (winter spores) develop. The ascospores germinate the next spring and when carried to other trees start the disease anew. The mycelium in an affected tree renews its activity each year and thus continues to spread, usually downward, until the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Martin, John N. (John Nathan), b. 1875. New York, John Wiley ; London, Chapman & Hall

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Keywords: ., bookcentury1900, bookdecade1910, booksubjectplants, bookyear1919