MARSONIA. 491 



Marsonia juglandis (Lib.) produces on leaves of Juglans little 

 greyish yellow spots with brown margins ; thereon stromata are 

 formed, which rupture the epidermis and liberate the large sickle- 

 shaped conidia. (Britain.) 



M. populi (Lib.). On leaves of species of Populus in Europe and Britain. 



M. potentiUae (Desm.). On species of Potentilla. (Britain.) 



M. campanulae Bres. et All. On Campanula latifolia. 



The following are North American species : 



M. toxicodendri (Ell. et Mart.). On Rhus Toxicodendron. 



M. quercus Peck. On Quercus ilieifolia. 



Phragmospor.ie. 



Ooryneum. 



The conidial patches are black and disc-like, and rupture the 

 host-epidermis. The conidia are oblong or spindle-shaped, 

 yellowish, and pluriseptate ; they are abjointed from short 

 conidiophores. 



Goryneum Beyerinkii Oud.'' This is stated by Beyerink to 

 be the cause of a " gum-flux " of cherry and allied species of 

 Rosaeeae. It is the conidial form of Ascospora (see p. 211). 



C. camelliae Mass.^ occurs on living Camellia leaves at Kew. 

 (Britain.) 



Pestalozzia. 



Conidia spindle-shaped, with two or more brown median cells 

 and hyaline terminal cells, the one at the free end carrying 

 several ciliate processes. 



Pestalozzia Hartigii Tub.^ The external effects of this 

 disease have been long known, although the fungus causing it 

 has only been recently detected. It attacks young plants of 

 various trees and shrubs. The symptoms are yellow discoloration 

 of the foliage, and constriction of the stem just above the level 

 of the soil, followed by death of the whole plant. At the 

 constriction of the stem the rind gradually dries up, whereas 

 neighbouring portions continue to grow in thickness till finally 

 the bark is ruptured (Fig. 302). In the living part of the 



^ Oudemans, Hedwigia, 1883. 

 ^ Cooke, Grevillea, xx., p. 8, 1891. 



■> V. Tubeuf, Beitrdge zur Kenntniss d. Baumhranhheiten, 1888 ; and ForstlirJi- 

 natarwiss. Zeitachrift, 1892. 



