On a New Species of Mclanotacnimn. Rudolph Beer, '^yj 



upon the size of the spores and upon tlie host plant which they 

 attack. Omitting the doubtful forms the most important facts 

 regarding the known species are briefly summarised in the 

 above table. 



From what has been said above, it will be recognised how 

 slight are the morpliological features which distinguish the 

 species of Melanotaciuium from one another. No doubt a more 

 complete knowledge of the gc^rmination, development and cyto- 

 logy of the diffcri'ut forms would reveal other characters which 

 would differentiate them morphologically rather more sharply 

 from one another. In the meanwhile we must admit the total 

 inadequacy of the existing morphological criteria for this purpose. 



The slight differences observed in th(; dimensions of the spores 

 of the various forms may quite possibly be due, partly to dis- 

 similar conditions under which development has taken place, 

 and partly to the personal equation which inevitably enters into 

 the case when a number of different observers measure a com- 

 paratively small number of selected spores with different instru- 

 ments. 



The conclusion to which these remarks trend is that in the 

 Melanotaeniums, as indeed in the Smuts in general, the "species 

 conception " can only be used as a convenient means of separating 

 the several forms which occur upon different host plants. It 

 can have here even less significance, as a hard and fast morpho- 

 logical distinction between natural entities, than is the case 

 with the more highly differentiated organisms in which several 

 investigators, such as Klebs, Goebel and Brierley, have shown 

 that the various morphological characters are merely the ex- 

 pression of the interaction between two factors: the internal, 

 molecular constitution of the protoplasm upon the one hand 

 and the external environment upon the other, and that if either 

 of these factors vary the morphological characters may become 

 changed. Based upon its occurrence upon a new host plant, I 

 therefore consider it advisable, provisionally at any rate, to re- 

 gard the Melanotaenium which has been found upon Lamium 

 album as a new species (in the above sense) and would suggest 

 for it the name Melanotaenium Lamii sp. nov. 



Melanotaenium Lamii sp. nov.* 

 The fungus forms intumescences or tuber-like swellings upon 

 the subterranean stems and buds of Lamium album. Spore mass 



* Melanotaenium Lamii sp. nov. 



Sori atri; sporae globosae vel ovatae, 17-20^ diam., episporio crasso, glabro, 

 atro-brunneo tectae, per matricis putref actionem liberatae. Sporarum ger- 

 minatio non visa. Sporae hyphaeque totani matricem penetrantes inter- 

 cellulares, mycelium haustoriis praeditum. In caulibus gemmisque subter- 

 raneis Lamii albi, tubercula forma variis ad 8-9 cm. diam. efficiens. 



