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 

 destrueti\e 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 orth, "A New Hollyhock Disease," Journal of Myroloiiy, vi., IsHU. 

 -Southworth, Jovrnal of Mycoloijy, vi., 1890, p. 100. 

 Atkinson, Alabama Afiri<'. Exper. Station Bulletin, No. 41, 1892. 



