424 Transactions of the Society. 



stouter and of denser contents than the spores ; spores filiform, curved, 

 sometimes strongly falcate, 25-40 /a by l'Dfi, 



On dead branches of Primus Cerasus and Py?'us Malus, Seamill, 

 Ayrshire, October 1899. Mr. D. A. Boyd. 



Libertella corticola sp. n., plate III. fig. 5. 



Pustules forming effused whitish spots under the outer bark, the 

 spores escaping and forming a milk-white layer ; spores straight or 

 slightly bent, colourless, 20-25 p by 1'5/x, borne on closely packed 

 sporophores that line the irregular infolding tissue of the pustule. 



On dead branches of Pyrus communis, Seamill, Ayrshire, Sep- 

 tember 1899. Mr. D. A. Boyd. 



Libertella Bibis sp. n., plate III. fig. 0. 



Forming lentiform effused pustules under the outer bark, burst- 

 ing the cuticle and the spores oozing out in a gelatinous pinkish 

 mass ; spores much curved, sometimes forming a complete semicircle, 

 30-40 fju by 1 [x, colourless. 



On branches of Ribes rubrum, Seamill, Ayrshire, October 1899. 

 Mr. D. A. Boyd. 



Libertella Salicis sp. n., plate III. fig. 7. 



Pustules formed in the cortex, convex or triangular in section, 

 causing slightly elevated reddish-coloured spots on the bark ; spores 

 curved, 25-35 yu, by 1 * 5 /x, colourless. 



On dead bark of Salix cinerea, West Kilbride, Ayrshire, autumn 

 189G. Mr. D. A. Boyd. 



Fusicladium pyrinum Lib., plate III. fig. 8. 



^ Effused, velvety, rusty-brown; mycelium spreading just under the 

 cuticle, finally penetrating and blackening the tissue ; conidiophores 

 upright, short, nodulose, irregular in form, denticulate at the tips, 

 usually about 20 ft in height; conidia ovate-fusiform, 15-30 /x by 

 about 7 fi, one-celled, brownish-yellow, smooth, usually solitary, but 

 often two or more on the same conidiophore. 



Parasitic on the leaves and fruit of Pijrus communis and, accord- 

 ing to Goethe, other fruit-trees. 



This fungus is, according to Br. Goethe, Garten Flora, 1887, 

 the conidial stage of a Pyrenomycete, and differs specifically, though 

 only slightly, from F. dendriticilm, both in this conidial stage and in 

 the ascomycetous form. 



It has been noted on the Continent for many years as a most 

 harmful parasite. This year it has appeared in Britain, doubtless 

 favoured by the late cold spring. I have seen specimens on pear- 

 trees from Worcester and Hereford, 



Specimens and slides of these fungi are in the Herbarium of the 

 British Museum, Cromwell Boad, South Kensington. 



