. KiG. ^o.—Microsphaera ^rossuluriac. i, gooseberry leaf with patches of mildew ; 2, a perithccium with its appi-nd- ages; 3, tip of an appendage ; 4 and 5, asci containing sjiorcs. Fig. I nat. size ; the remainder highly mag. season, and is readily recognised under the microscope by the elaborate tips of the appendages. Mycelium delicate, greyish-white on both surfaces of the leaf; perithecia usually in small, scattered groups, dark brown, appendages once or twice as long as diameter of j)eridium, 4-6 times forked at the tip; asci 3-10, ovate, containing 3-6 spores of variable size, 20-30 x 1

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. KiG. ^o.—Microsphaera ^rossuluriac. i, gooseberry leaf with patches of mildew ; 2, a perithccium with its appi-nd- ages; 3, tip of an appendage ; 4 and 5, asci containing sjiorcs. Fig. I nat. size ; the remainder highly mag. season, and is readily recognised under the microscope by the elaborate tips of the appendages. Mycelium delicate, greyish-white on both surfaces of the leaf; perithecia usually in small, scattered groups, dark brown, appendages once or twice as long as diameter of j)eridium, 4-6 times forked at the tip; asci 3-10, ovate, containing 3-6 spores of variable size, 20-30 x 12-15 /*• As a rule this jmrasite cannot be considered as injurious. Spraying with potassium sulphide is effective if commenced when the leaves are unfolding.

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Keywords: ., bookpublishernewyorkmacmillan, booksubjectplantdis, bookyear1910