206^ THE .lOUllXAL OF BOTA>'r 



MYCOLOGICAL NOTES.— lY. 



By W. B. Grove, M.A. 



I. Phi'llosticta and Phleospora. 



The species assigned to tlie form-genus of the Coelomyeetes named 

 Plileospora have long afforded a curious ground of controversy, the 

 point in dispute being whether there is a true pycnidium or not. 

 Both sides of the dispute have been hotly maintained : Klebahn says 

 that Phleo^pora TJlmi has no pycnidium, and therefore he places it 

 in Scptogloeum. As in most controversies both sides are right : the 

 shield is golden on one side, silvern on the other. The fact is that 

 the answer at which one arrives in considering this question depends 

 upon the state of development of the fungus under examination. In 

 the early stages of growth, some at least of the species of Plileospora 

 have a pjxnidium, in the latter stages it ma}^ be nearly or completely 

 wanting. But this is not all ; the spores produced by the same 

 h}Tnenium may change in character also in a remarkable way. The 

 same little black dot on a leaf, obiter visuni, would be placed, accord- 

 ing to its age at the moment of observation, in Phyllosticta, or in 

 I^hleospora, or in Seplogloeum, or even in Leptothiirium or Septoria. 



The differences between the first two form-genera appear very 

 considerable. In JPhyllosticta there is a complete, thin, all-round 

 pycnidium, formed of delicate closely interwoven (plectenchymatous) 

 hyphse, at the summit furnished with a small round pore about which 

 the cells are often darker in colour, while the spores are unicellular, 

 oval-oblong, usually small, and most often provided with two polar 

 oil-guttules : in Plileospora the spores are elongated and vermiform, 

 often pluriguttulate, occasionally 1- or 3-septate, and the pycnidium 

 in its finished state is merely a shallow cup with a wide opening, 

 edged by a narrow margin. Yet the former can change by degrees 

 into the latter, and finally, if all tmce of the pycnidium had vanished, 

 it would undoubtedl}' be considered a Septogloeum. 



Specimens oiPhleospora 0^y«c«wM^Wallr. when closely examined 

 show, intimatelj'^ mixed among pycnidia which accoi-d Avith the 

 description of that species, others belonging to Phyllosticta, and in 

 fact indistinguishable from Fhyllosticta monogyna Allesch. except in 

 having slightly smaller spores. The appearances are exactly what 

 would be seen if the same p^^cnidium, which at first when small 

 produced the Phyllosticfa-spores, afterwards from the same pro- 

 liferous stratum (enlarged) began to produce the Phleospora-spores, 

 which then by their size and abundance burst tlie pycnidium open 

 and finally left it cup-shaped. Tlie loose cellular structure of the 

 wall is of identically the same character in both ; two pycnidia, one 

 of each kind, can be found in close contact, and all the stei:>s between 

 can be traced in the sections. 



Moreover, the spores of the PJiyllosticfa-sisige vary continuously 

 in size. Allescher gives the size of the spores in his P. monogyna 

 as 6-8x2|yu; in my specimens most of the spores measured 

 4-6 X 1-1^ /^. It may therefore easih^ be surmised that Pliyllosticta 

 crutceqicola Sacc. (Syll. iii. G) is nothing but a still earlier state, in 



