. Minnesota plant diseases. Plant diseases. Fig. 74.—More spores of rust fungi. 1. A pycnidium (from wheat rust on barberry), a capsular spore-bearing fruiting body showing dust of spores at r. 2. Spores and spore-bearing threads from 1 greatly enlarged. 3. Same spores germinating. These spores are probably the relics of male reproductive cells which have fallen into disuse. They appear to be functionless since they do not usually germinate and have never been known to cause infection. 4. A cluster-cup of an Anemone rust; s spores, formed in chains; p, threads forming the cup of the cluster-cu
. Minnesota plant diseases. Plant diseases. Fig. 74.—More spores of rust fungi. 1. A pycnidium (from wheat rust on barberry), a capsular spore-bearing fruiting body showing dust of spores at r. 2. Spores and spore-bearing threads from 1 greatly enlarged. 3. Same spores germinating. These spores are probably the relics of male reproductive cells which have fallen into disuse. They appear to be functionless since they do not usually germinate and have never been known to cause infection. 4. A cluster-cup of an Anemone rust; s spores, formed in chains; p, threads forming the cup of the cluster-cup. All highly magni- fied. After Tavel. those at the summit being the first to mature. These cluster- cup spores are ball-shaped or have flattened sides and their outer wall is frequently provided with small warty roughnesses. The cluster-cup spores are blown about by the wind and are •capable of immediate germination. When germinating they send out a germ thread which causes infection. Accompanying. 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
