GIBELL1NA 241 



portions of the branches is the first form of fruit to appear ; 

 these develop during the summer after infection. In the 

 autumn the ascigerous form of the fungus appears on the 

 dead shoots. Finally the young leaves are infected by the 

 spores of the ascigerous fruit; blackened patches appear, 

 more especially towards the tip of the leaf, and near the 

 margin. In May or June the blackened and dried-up patches 

 become covered with a very delicate clear yellow bloom, 

 which later changes by degrees to a deep olive colour. This 

 conidial form of the fungus was at one time considered as an 

 entity, and was described by Frank as a new parasitic fungus 

 under the name of Fusidadium tremulae (Frank). It is also 

 known as Napidadium tremulae (Sacc.). 



Ascigerous form. Perithecia globose, up to -J- mm. diam. 

 Asci cylindrical, 8-spored ; spores clear brown, of two unequal 

 cells, largest cell nearest apex of ascus. 



Pycnidia or Phoma form. Perithecia minute, conidia, 

 5-6 X 2-2 '5 /*, hyaline, elliptic-oblong. 



Fusidadium form. Conidia produced on a stroma on dead 

 patches of bark ; 3-celled when mature, the central cell 

 largest, fusiform, ends blunt, brown. 



Unfortunately, owing to the difficulties of either spraying 

 or pruning such tall trees, the disease is difficult to check. 

 The disease is undoubtedly perpetuated from year to year by 

 the fruit formed on young shoots that have been killed by 

 the fungus. 



Frank, Ber. d. deutsch. Bot. Ges., i, p. 29 (1883). 

 Prillieux, Malad. des Plantes Agr., 2, 202 (1897). 

 Vuillemin, Comp. Rend., 108, p. 632 (1889). 



GIBELLINA (PASS.) 



Stroma immersed, perithecia seated on the stroma or im- 

 mersed, globose, with a long rather stout, curved or straight 

 beak; asci 8-spored; spores oblong, i -septate, coloured. 



Wheat straw disease. A parasitic fungus called Gibellina 

 cerealis (Pass.) has proved very destructive to wheat in Italy, 

 where it appears at intervals of years, and during the interval 

 is, so far as observations go, entirely absent. About the 

 month of May, plants that are infected become yellowish- 

 green and drooping. When such plants are examined the 



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