. The fungi which cause plant disease . Plant diseases; Fungi. 308 THE FUNGI WHICH CAUSE PLANT DISEASE parts and eventually becoming dissipated and leaving behind only the naked rachis; spores lighter colored on one side, usually sub- spherical to spherical, occasionally elongate, minutely echinulate especially on the lighter side, 5-9 /i in length. On wheat where- ever cultivated. The smut mass is covered at first by a very delicate membrane. Infection is floral as described for U. nuda. The spores germinate in water by a long 2 to 3, or even 6 to 7-septate, promycelium, often curved. In nutr
. The fungi which cause plant disease . Plant diseases; Fungi. 308 THE FUNGI WHICH CAUSE PLANT DISEASE parts and eventually becoming dissipated and leaving behind only the naked rachis; spores lighter colored on one side, usually sub- spherical to spherical, occasionally elongate, minutely echinulate especially on the lighter side, 5-9 /i in length. On wheat where- ever cultivated. The smut mass is covered at first by a very delicate membrane. Infection is floral as described for U. nuda. The spores germinate in water by a long 2 to 3, or even 6 to 7-septate, promycelium, often curved. In nutrient solutions the. FiQ. 223.—U. zeiB, stages in spore development. After Knowles. promycelium branches profusely but sporidia are few or are en- tirely absent. U. zeffi (Beck.) ;' 24' ii»-i2i-133. i36,142 Sori on any part of the corn plant usually prominent, forming irregular swellings from a few millimeters to over a decimeter in diameter, at first protected by a sort of false white membrane composed of plant cells and semi-gelatinized fungous threads, soon rupturing and disclosing a reddish-brown spore-mass; spores ellipsoidal to spherical or rarely more irregular, prominently though rather bluntly echinulate, 8-11 n the most elongate 15 /* in length. The germination of the spores, which occurs but poorly in water, was first studied by Kiihn * in 1857. In 1874 Kiihn saw the pene- tration of the germ tubes through the epidermis of the com plant. Brefeld showed that the spores germinate well in nutrient- solu- tions and that secondary spores are formed; also that corn can be infected by the sporidia at any point on its surface above ground. 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 Stevens, Frank Lincoln, 1871-1934. New York : Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfungi, bookyear1913
