466 THE COFFEE-DISEASE IN SOUTH AMERICA. 



mycelium in the tissues, or they may nourish a Septoria, as seen 

 by the Eev. M. J. Berkeley, or a Sphcerella, as found by myself; 

 or, finally, a species of Stilbum, as seen by myself and by Pro- 

 fessor Saenz. Further, the Stilbum may occur on the same spot 

 as the perithecia of the Sphcerella, or both perithecia and Stilbum 

 (the one without the other) maybe found occupying different spots. 

 All these points are worthy of consideration in searching for the 

 source of the disease. 



I cannot forbear noticing incidentally that Sphcerella isariphora, 

 Desm., a small species of Sphcerella common on the leaves of some 

 Bpecies of Stellaria, owes its name to the fact that it is sometimes 

 found associated with a minute species of Isaria, a mould closely 

 allied to Stilbum, although the Sphcerella is often found without 

 the Isaria. 



On unripe coffee-berries from Costa Rica, as well as from Vene- 

 zuela, the same orbicular spots occur, usually one spot only on each 

 berry ; and on some of these spots I have seen the Stilbum, but 

 hitherto have not observed the Sphcerella. 



These observations are communicated to the Society as a sum- 

 mary of all that at present has been determined respecting the 

 coffee-disease of South America. I venture to think that the 

 disease seems to be a complicated one ; and for the present 

 I am not prepared to affirm that either the Septoria, or the Sphce- 

 rella, or the Stilbum, or all together, is the cause of the disease. 

 At the same time I cannot but think it possible that none of 

 the three forms of fungus are autonomous, and that all may be 

 related to each other as form3 or conditions of the same fungus, 

 of which the Sphcerella is the highest and most perfect manifes- 

 tation. 



Since the foregoing was written, I have been permitted by the 

 Eev. M. J. Berkeley to examine some diseased coffee-leaves* 

 from the island of Jamaica. The same discoloured spots are pre- 

 sent, although smaller in size, and little dark specks or points 

 (visible under a lens) on these at once suggested a Septoria or 

 Sphcerella ; but microscopical examination showed that the dark 

 points were not perithecia, but tufts of short-jointed olive threads, 



* [The leaves in question were sent by Mr- Morri3, Government Botanist at 

 Jamaica, accompanied by a sketch of the Cercospora ; but neither Mr. Morris 

 nor Mr. Berkeley could find spores ; and Dr. Cooke found them only after 

 long and patient examination. Mr. Berkeley thinks that the Cercospora is pos- 

 sibly the same with Cladosporium stenospora, B. &, Curtis. — M. J. B.] 



