THE FUNGI WHICH CAUSE PLANT DISEASE 149 



earlier known as Gloeosporium ribis (Lib.) Mont. & Desm. Old 

 leaves bearing the latter fimgus were wintered out-doors in filter 

 paper and in the spring were found with this ascigerous stage. 

 The ascospores were isolated, grown in pure culture and typical 

 conidia were produced. The ascospores also infected the host 

 leaves successfully producing there the typical Gloeosporium. 

 The conidial stage is the only one ordinarily seen. The acervuli 

 are subepidermal elevating the epidermis to form a pustule which 

 eventually ruptures and allows the spores to escape as a gelatinous 

 whitish or flesh-colored mass. The spores are curved and usually 

 larger at one end than at the other. 



Fabraea Saccardo (p. 147) 



This is a genus of some ten species of small leaf parasites 

 which much resemble Pseudopeziza but differ from it in its 2 to 

 4-celled spores. 



F. maculata (Lev.) Atk.*^ 



The perfect stage is common on pear and quince leaves which 

 have wintered naturally. When such leaves are wet the white 

 8-spored asci may be seen 

 crowding through the surface 

 in small eUiptical areas. The 

 apothecium is paraphysate; the 

 spores hyaline and 2-celled. 



Conidial form (=Entomo- 

 sporium maculatum) on leaves 

 and fruits; acervuli, black, 

 subepidermal, the epidermis 

 breaking away to expose the pio. loe.— F. maculata. i, acemiius of 



„„„-«„ ViiTolinr^ conidial stage in section; 3, spores. 



spore mass; spores hyahne After Southworth. 



18-20 X 12 fi, 4-cells in a 



cluster, the lateral cells smaller, depressed; stipe filiform 20 x 



0.75 m; the other cells with long setae. 



Atkinson ^' proved the connection of the ascigerous with the 

 conidial form by ctiltiv'ating the conidia from the ascospores. The 

 conidial form is very common and destructive on pear and quince 

 leaves and fruit. The mycelium which abounds in the diseased 

 spot is hyaline when young, dark when old. It collects to form a 



