NAPICLADIUM. -517 



become coated with conidia and assume a leaden grey colour, 

 so that in many cases only the points remain green. Finally 

 the attacked leaves die and dry up. 



4. Sect. Dicttosporae. 



1. Subsect. Micronemeae. 



The forms included under genera of this group (e.g. Sporo- 

 desmium and Coniothecmm) have as yet been little investigated 

 in regard to their parasitic nature. 



2. Subsect. Macronemeae. 



Macrosporium. 



Conidia grey, muriform, and borne on the apex of simple or 

 branched conidiophores. 



Macrosporium sarcinaeforme Cav.^ Cavara describes a 

 browning and death of a whole field of red clover {Trifolium, 

 joratense), and ascribes it to this fungus. Minute spots were 

 produced, at first light-coloured, then brown, finally coalescing 

 so as to cause . drying-up of the whole leaf. The short thick 

 conidiophores were developed on the lower surface of the leaf, 

 and gave off pluricellular terminal conidia. 



M. solani Ell. et Mart. This is described'"' as occurring along 

 with the " black -rot " of- the tomato in the United States. It is 

 said to cause a rot in the fruit and a leaf-blight on both tomato 

 and potato. Along with this species there also occur a Fusarium- 

 (p. 520) and frequently a Cladosporium ; as yet the relationships 

 of the different forms, and the part they take in causing the 

 diseases ascribed to them, is but imperfectly investigated. 



Sorauer^ ascribes a disease on the potato in Germany to this 

 species or to an AUernaria (A. solani). He also believes that 

 it is the cause of the " early blight " of American potato crops, 

 but further investigation is still required. 



Many other species of Macrosporium have been described on 

 plants of economic importance, yet most of them occur only on 

 parts somewhat! faded or languid, so that they cannot be regarded 



'Briosi and Cavara, Funghi parasit., v. 



^ Beport of the Section of Vegetable Pathology for 1888, U.S. Department of 

 Agriculture. 



^ Ziitschrift f. Pjianzenkrankheiten, 1896, p. 1. 



