Some SapropJiytic Fungi of Potatoes. G. H. PetJiybyidge. iii 



with Silver Scurf, viz. a Colletotrichum, a Fusarium and 

 Spoiidylocladium atrovirens. It seems possible that the sclerotia 

 originally present may have been partly those of Spondylo- 

 cladium (formerly known as Phellomyces) and partly those of 

 a Colletotrichum. Or, the Colletotrichum may have been 

 present in mycelial form (as also the Fusarium probably was) 

 and was not killed by the preliminary treatment with mercuric 

 chloride. The matter, at any rate, deserves further careful 

 study before the view that Phellomyces is a Colletotrichum 

 and not Spondylocladium can be accepted. 



Vermicularia varians has been described by Ducomet* as 

 producing a disease of potatoes in France, and the same disease 

 apparently occurs in Australia! and South Africa|. The 

 published descriptions of this "dartrose" or "Black Dot" 

 disease recall, to some extent, what one has seen of Colleto- 

 trichum tabificum; but whether there is any real connexion 

 between these two fungi can only be decided by further study. 



III. HYPOMYCES SOLAN! Reinke et Berth, 



This fungus was described by Reinke and Berthold§ in 1879, 

 who stated that it was a pure saprophyte. Since the ascospores 

 on germination gave rise to conidia which these authors took 

 to be those of Fusisporium Solani, they regarded Hypomyces 

 Solani as the perithecial stage of this species. 



Fusisporium Solani Martins was renamed Fusarium Solani 

 by Saccardo ; and in the older literature this fungus was often 

 regarded as a parasite and the cause of the "Dry Rot" of the 

 potato tuber. 



The investigations of recent years on the genus Fusarium 

 have, however, shown that the name F. Solani has been used 

 in the past for more than one species of this genus; and this 

 doubtless explains some of the confusion that has arisen. 



Hypomyces Solani in its perithecial stage does not appear to 

 be very common. I have only found it on three or four occasions, 

 and always on the surface of potato tubers in an advanced 

 stage of decay ; never on tubers still partially living. Several 

 years ago I was able to obtain type material of the fungus which 

 has been useful for purposes of comparison. 



The object of the present study was to trace the complete 

 life-cycle of H. Solani from ascospore to ascospore in vitro ; to 

 make a careful comparison between its conidial stage and some 



* Ducomet, V. Ann. Ecole Nat. Agric. Rennes, ii. 1908. 



t McAlpine, D. Potato Diseases in Australia, lyii, p. 92. 



X Doidge, E. M. Agric. Journ. Un. South Africa, vii. No. 6, 1914, p. 879. 



§ Loc. cit. p. 27. 



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