462 FUNGI IMPERFECTI. 



4. FAM. EXCIPULACEAE. 



The parasitic nature of the species of this family has not as 

 yet been investigated to any extent. 



II. MELANCONIEAE. 

 True pycnidia are not formed, but the conidia are developed 

 in clusters or aggregations covered over at first by the epi- 

 dermis of the host-plant, which is ultimately ruptured. 



Htalosporae. 

 Gloeosporium. 



Conidial clusters colourless or grey, never black ; they rup- 

 ture the overlying epidermis and give off unicellular conidia, 

 one from each conidiophore. 



Gloeosporium fructigenum Berk.^ (Britain and U.S. America). 

 Apple Eob or Eipe-rot. This is a very serious disease for 

 American cultivators. It not only attacks apple, but also the 

 grape, pears, peaches, and egg-plants.^ On the apple it appears 

 first as brown spots which become more conspicuous as the 

 fruit enlarges. The spots on first siglit look like decay, but 

 they are quite firm and soon bear pustules of a white or 

 pinkish colour turning to black. The attacked part of the apple 

 has an intensely bitter taste, and should be carefully removed 

 before eating the fruit. On grapes the fungus produces tiny 

 raised pustules, which on the white varieties are situated on 

 spots with a purple centre and a brown margin ; the pustules 

 when mature give off flesh-coloured conidia. The grapes 

 gradually shrivel up, but do not become black as" in the case 

 of the black-rot, nor do they assume a bitter taste as the 

 apples do. 



The apple bitter-rot makes rapid progress amongst stored 

 fruit, especially before it has been sorted out. Care should 

 therefore be taken that diseased apples are removed as soon 

 as possible. 



The spraying of trees bearing young fruit with copper car- 



' Southworth, Journal of Mycology, vi. , p. 1 64. 

 ^Halsted, Bidletin of the Torrey Club, 1893, p. 109. 

 Massee, Gardener's Chronicle, Vol. xiv., 1893. 



