Fungous diseases of plants . quentlyin the United States. As aresult, certain observationsmay be stated. In the firstplace, the common alfalfaroot fungus of Europe {Rhi-zoctonia Medicaginis) is thesame as the European rootfungus of asparagus {Aspara-gus offLcinalis). This speciesalso occurs less frequentlyupon the sugar beet {Betaoulgaris), and, doubtless,upon other cultivated andwild plants. The fungus ap-pears upon the root as a closeweft of violet-colored hyphae(Fig. 239), composed of cellsmore or less uniform in diam-eter, filamentous, branched,but without a particularlycharacteristic type
Fungous diseases of plants . quentlyin the United States. As aresult, certain observationsmay be stated. In the firstplace, the common alfalfaroot fungus of Europe {Rhi-zoctonia Medicaginis) is thesame as the European rootfungus of asparagus {Aspara-gus offLcinalis). This speciesalso occurs less frequentlyupon the sugar beet {Betaoulgaris), and, doubtless,upon other cultivated andwild plants. The fungus ap-pears upon the root as a closeweft of violet-colored hyphae(Fig. 239), composed of cellsmore or less uniform in diam-eter, filamentous, branched,but without a particularlycharacteristic type of branch-ing. Morphologically, itbears no resemblance to thesterile stage of Corticiumvagum, above referred to,that is, the form causing the rot of the crocus, and a similar diseaseof the carrot, etc., in Europe, the rot of beets, stem rot of carna-tions, certain damping-off diseases, etc., in America. Rhizoctonia Medicaginis does not occur in America so far ascan be ascertained. In Europe it is one of the most destructive. Fig. 239. Rhizoctonia Medicaginis onRoots of Asparagus AUTOBASIDIOMYCETES 479 of the clover diseases and frequently becomes epidemic in planta-tions of alfalfa, or lucern, a highly important forage plant ofCentral Europe. In asparagus growing the losses are also occa-sionally severe. An ascomycetous fungus occurring upon the stubble of alfalfa,described as Lcptosphceria circinans Fckl., has been by some re-garded as the perfect stage of RJiisoctonia Medicaginis, yetthrough cultures of ascospores the writer has been unable to pro-duce a mycelium resembling that of the Rhizoctonia, Moreover,the mycelium of the Rhizoctonia has been unusually difficult topropagate in artificial cultures, XV. ROOT ROT OF COTTON AND ALFALFAOzonium onmivorum Shear Atkixsox, Geo. F. Method for Obtaining Pure Cultures of Pammels Fun-gus of Texas Root Rot of Cotton. Bot. Gaz. 18 : 16-19. 1893. Pammel, L. H. Cotton Root Rot. Texas Agl. Exp. Sta. Rept. 2: (Also published a
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