. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. COLLETOTRICHUM. 487 api)ear on the leaves, and depressions on the stem, sometimes extending so far round that the whole shoot dries up. The conidial patches are very much the same on the different hosts, and consist of short conidiophores from which oval, unicellular, hyaline conidia are abjointed. C. lycopersici Cliei^r. is lUe cause of a spot-disease on the fruit of tomato in the United States. C. spinaciae Ell. et.

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. Diseases of plants induced by cryptogamic parasites; introduction to the study of pathogenic Fungi, slime-Fungi, bacteria, & Algae. Plant diseases; Parasitic plants; Fungi. COLLETOTRICHUM. 487 api)ear on the leaves, and depressions on the stem, sometimes extending so far round that the whole shoot dries up. The conidial patches are very much the same on the different hosts, and consist of short conidiophores from which oval, unicellular, hyaline conidia are abjointed. C. lycopersici Cliei^r. is lUe cause of a spot-disease on the fruit of tomato in the United States. C. spinaciae Ell. et. Hals, causes a destruetie disease on cultivated spinach. C. malvarum Br. et Casp. (C. aWiacac Southw.^) produces a disease of cultivated hollyhock. It is most injurious to the seedling plants, and has caused great loss in America and Sweden. The fungus may attack any organ, and produces spots which enlarge so rapidly that death of the host may rc'^nlt. C. gossypii Southw.- Anthracnose of Cotton. This disease, although it may be found on stems and leaves, is most frequent and most conspicuous on the fruits or " bolls" of the cotton-plant. The first signs are tiny depressed spots of a reddish-brown colour, and as these enlarge they cause blackening of neigh- bouring tissue. When the spores are developed the spots become dirty grey, or perhaps jjinkish if the spores are present in large numbers. Fruit attacked in this way does not mature well, and the yield of cotton is greatly prejudiced. Atkinson found the cotyledons ea.sy to infect with the disease. The spores are oblong and tapering, with a .shallow constriction in the middle; they are borne either on short colourless basidia or on long, olive-coloured, septate setae, both kinds of conidin- phore being produced in acervuli or patches. C. adustum Ell. is the cau.se of a leaf-sjiot on orange in Floiidii.. Fig. iii&.—ColUlotrichum Linde- vthianvni on pod of Kidnej' e:iii. Enlarged pustule and midia. ^ .Southw or