E. S. Salmon and H. Wormald 5 



minute pustules, below the epidermis, bursts through to the surface, 

 the exceedingly minute spores, only about 1-3,000 of an inch in length, 

 oozing out through minute cracks in the epidermis, under the form of 

 very slender, white, gelatinous threads or tendrils." The figure given 

 of these spores is reproduced at Fig. 11, Plate II. It will be seen 

 from Fig. 1 1 , traced from Mr Massee's figure of the Fig canker Liherlella 

 in the Gardeners' Magazine^ that the length of the conidia is about 

 1-3,000 of an inch {i.e. 8-9 /x), or approximately that of the conidia of 

 Phoma cinerescens (compare Figs. 10 and 11, allowing for the difference 

 in magnification). In A Text-Book of Plant Diseases'^ Mr Massee in 

 describing his species under the name Libertella ulcerata Massee (sp. nov.) 

 says, "Conidia fusiform, ends acute, continuous, curved, hyaline, 

 55-60 X 4 ju," and this description is repeated in his Diseases of Cultivated 

 Plants and Trees'^. This discrepancy in the accounts of the dimension 

 of the conidia of Libertella ulcerata we are unable to account for. Our 

 fungus, i.e. Plioma cinerescens, belongs to the Sphaerofsidiaceae ("peri- 

 thecia containing conidia borne at the tips of slender conidiophores") 

 and its conidia are ellipsoidal to fusiform, straight or slightly curved, 

 ends usually rounded, averaging 9x3/*, and never exceeding 13 /a in 

 length. 



The Herbarium at Kew was found 2iot to contain the type specimen 

 of L. ulcerata Mass. In March 1915, Mr Massee kindly forwarded to 

 us an example of his fungus, writing "Enclosed is a fragment of the 

 tyfc specimen," and adding as a postscript, "I am almost certain that 

 the Libertella is followed by a Phoma stage, but have not been able to 

 get one from the other in cultures." The portion of the type specimen 

 sent consisted of some hundreds of fructifications, mostly with dried-up 

 tendrils of conidia still attached, and proved to be entirely Plioma 

 cinerescens, with all the characters as described above. A thorough 

 search of this type material showed no conidia resembling those described 

 by Mr Massee, or any fructification of the type found in Libertella. 



With reference to the parasitic nature of his fungus, Mr Massee 

 states: "Experiments conducted on healthy young fig-trees show that 

 the spores of the fungus — a species of Libertella — will not cause the 

 disease when placed on the unbroken surface of even very young 

 branches, whereas when the spores are placed on the end of a cut branch 

 or on injured bark, inoculation always followed, and the mycelium was 

 found in abundance at the expiration of 10 days. In one experiment 



1 Massee, G., A Text-Book of Plant Diseases, p. 431 (1903). 

 * Idem, Diseases of Cultivated Plants and Trees, p. 448 (1910). 



