. Minnesota plant diseases. Plant diseases. Minnesota Plant Diseases. 159 Rusts (UredinecB). The rust fungi constitute a larger group of plants than the smuts and exhibit more variety of structure and habit. They may be considered as relatives of the smuts in that the winter spores of the latter may be compared with. Fig. 73.—Spores of rust fungi. 1. A cluster of winter spores of wheat rust (Puccinia graminis) on wheat plant. 2. A winter spore germinating to a thread of four cells (promycelium—basidium), each of which bears a small spore (sporidium) on a stalk. The winter spore germinates in t
. Minnesota plant diseases. Plant diseases. Minnesota Plant Diseases. 159 Rusts (UredinecB). The rust fungi constitute a larger group of plants than the smuts and exhibit more variety of structure and habit. They may be considered as relatives of the smuts in that the winter spores of the latter may be compared with. Fig. 73.—Spores of rust fungi. 1. A cluster of winter spores of wheat rust (Puccinia graminis) on wheat plant. 2. A winter spore germinating to a thread of four cells (promycelium—basidium), each of which bears a small spore (sporidium) on a stalk. The winter spore germinates in the spring while still in the straw or on the ground. The sporidia are blown by the wind to another plant and there germinate as seen in 3 and 4. 4. Shows the germination of a sporidium on a barberry leaf; here infection will soon take place. 5. A germinating summer spore of wheat rust, showing germ tubes which on a wheat plant can cause infection (as shown in Fig. 29). 6. A rare grass rust spore (amphispore of Puccinia vexans) germinating; it germinates as a summer spore, but has a thick coat and rests over winter as a winter spore. All highly magnified. 1-5, after Ward; 6, after Carleton. (See also Fig. 74.) the smut spores. The rusts, however, exhibit a great number of accessory spore forms. They are all parasites and are of great economic importance on account of the large number of dis- ease-causing forms. The life-story of a rust plant is often very. 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 Freeman, Edward Monroe, 1875-. Saint Paul, Minn.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectplantdi, bookyear1905
