THE FUNGI WHICH CAUSE PLANT DISEASE 253 



Macrodendrophoma salicicola cause black cankers on oziers in 

 Ireland.22^ 



P. abietina P. & D.^^s jg f^^j^jj ^j^ pj^^g^. p cattleyae Maub. & 

 Las. in its conidial form, Glceosporium macropus^^* parasitizes 

 Cattleya. P. laburni Bon. is on Cytisus. 



P. woronini M. & F. is described as causing a disease of grapes 

 in the Caucasus. ^^' 



P. vanillse Zimm. is on vanilla; 



P. fallaciosa Sacc. on banana leaves. 



Venturia Cesati & de Notaris (p. 251) 



Perithecia superficial or erumpent, bristly, ostiolate, membra- 

 nous, dark colored; asci sessile or short stipitate, ovate or saccate; 

 spores oblong to ovoid elliptic, hyaline or yellowish; paraphyses 

 usually none. 



The conidial stages in some cases belong to the form genus 

 Fusicladium and constitute the parasitic portion of the life history 

 of the fungus, the ascigerous form usually being Umited to old or 

 wintered parts of the host. 



There are over fifty species, several of which cause diseases. 



V. pinna Aderh.^'"- '"'• '"■ ''" 



Perithecia gregarious, smooth or bristly, globoid, 120-160 n; 

 asci cylindric; spores unequally 2-celled, yellowish-green, 14-20 x 

 5-8/1. 



Conidia (=rusicladiimi pirinum) effused, velvety, blackish-olive, 

 conidiophores short, wavy or knotted, thick- walled; conidia ovate 

 fusoid, olive, becoming 1-septate with age, 28-30 x 7-9 ju. 



It is foimd on the pear wintering in perithecial form on leaves, 

 and in conidial form, or as mycelium on twigs. 



V. inaequalis (Cke.) Aderh. (=V. pomi [Fries] Winter). 



Perithecia globose, short-necked, 20-160 n, smooth or bristly 

 above; asci cylindric, 40-70 /* long; spores yellowish-green, un- 

 equally 2-celled, upper cell shorter and broader, 11-15 x 4-8 /t. 



Conidia (= Fusicladium dendriticimi) efifused, velvety, forming 

 dendritic patches of compact masses of erect closely septate 

 brown mycelium; conidiophores closely septate, brown, 50-60 x 

 4-6 fi, wavy or nodulose; conidia solitary, terminal, obclavate. 



