. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 396 FUNGOUS DISEASES OF PLANTS upon Trifolium incarnatum L., much less frequently, however, upon some of the other species mentioned. In general, the spermogonial and aecidial stages are not commonly found upon the red clover, the host upon which the other stages are perhaps most frequent. Nevertheless, the reported absence of gecidial stages upon this host in certain regions may be due to the fact that careful examina- tions have not been made at the proper season. The fungus. The
. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 396 FUNGOUS DISEASES OF PLANTS upon Trifolium incarnatum L., much less frequently, however, upon some of the other species mentioned. In general, the spermogonial and aecidial stages are not commonly found upon the red clover, the host upon which the other stages are perhaps most frequent. Nevertheless, the reported absence of gecidial stages upon this host in certain regions may be due to the fact that careful examina- tions have not been made at the proper season. The fungus. The my- celium corresponds very closely to that described as generally characteristic of the whole order. It is considered to be local. The spermogonia and aecidia generally appear during very early spring or at almost any time dur- ing open winter. They occur upon the under sur- faces of the leaves and on the petioles. The secidio- spores (14—23/i in diam- eter) germinate readily in water, and under favor- able conditions infection in the greenhouse or in the open may be secured, with the production of uredosori within two weeks. The uredo- spores, as shown in Fig. 195, d, measure about 22—26 x 18-20 p. These spores also germinate readily, and repeated crops of the uredospores may be produced, possibly in some cases extending into the winter, and even carrying the fungus through the year. Teleutospores are produced, however, and these may occur in sori with uredospores, or in independent sori, as the season. c a Uromyces Trifolii: Clover Rust. 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 Duggar, Benjamin M. (Benjamin Minge), 1872-1956. Boston ; New York : Ginn
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