. A manual of poisonous plants, chiefly of eastern North America, with brief notes on economic and medicinal plants, and numerous illustrations. Poisonous plants. 280 MANUAL OF POISONOUS PLANTS. Fig. 99. Black Spot of Grasses (.Phyllachora graminis). A. Cross section of leaf through a black mass of the fungus. P. Perithecia. B. An ascus with ascospores. a, b. Spots on grass leaf caused by the fungus. After Frank and Trelease. Phyllachora graminis (Pers.) Fckl. Stroma scattered or confluent, penetrating the leaf and more or less prom- inent on both, sides, covered by a black and shining epiderm
. A manual of poisonous plants, chiefly of eastern North America, with brief notes on economic and medicinal plants, and numerous illustrations. Poisonous plants. 280 MANUAL OF POISONOUS PLANTS. Fig. 99. Black Spot of Grasses (.Phyllachora graminis). A. Cross section of leaf through a black mass of the fungus. P. Perithecia. B. An ascus with ascospores. a, b. Spots on grass leaf caused by the fungus. After Frank and Trelease. Phyllachora graminis (Pers.) Fckl. Stroma scattered or confluent, penetrating the leaf and more or less prom- inent on both, sides, covered by a black and shining epidermis, roughened; ostiola obscure; asci short, stalked, cylindrical, 75-80 x 7-8 A*, ascospores 8, paraphyses present. Phyllachora graminis, occurs on many cultivated and wild grasses; other species occur on clover and other leguminous plants. This parasitic fungus disease causes blackish spots on the lower or both surfaces of the leaf. The fungus causing these black spots on grasses has been called the black spot disease. During August, and especially later, the coal black spots along the veins are especially prominent; they are considerably less than one-eighth of an inch in length and width and occur on both surfaces of the leaf, but are more abundant on the upper. These black spots are composed of dense mycelium, which in the green leaves bears numerous small spores which serve to proga- pate the fungus in the summer. In dead leaves, small perithecia are found, which contain numerous elongated bodies, the asci, within which are found eight small, colorless spores, known as ascospores; these latter carry the fungus over winter. Distribution and Hosts. Widely distributed in both Europe and North America, very common upon Quack Grass, Wild Rye, Bottle Grass, Panic Grass, etc. Poisonous properties. The genus Phyllachora is abundant at times and is associated with stomatitis. SPHAfiRIALeS Perithecia generally with a distinct ostiolum, of various consistency, not reddish or membrano
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