VERMICULARIA 417 



in common with the disease under consideration, except the 

 name of canker. 



Giissow, fourn. Roy. Hort. Soc., 34, p. 222 (1908). 

 Sorauer, Zeitschr. Pflanzenkr., 17, p. 22 (1908). 



Blackberry canker. Large irregular nodules, varying in size 

 from a marble to a walnut, are formed on the stem of the 

 common bramble by Coniothyrium tumaefaciens (Giissow), a 

 close ally of the fungus causing rose canker. 



Perithecia blackish-brown, scattered; conidia unicellular, 

 pale dirty green, elliptic, 5-7 X 3-4 ft, supported on long, simple 

 or branched conidiophores. 



Giissow, Journ. Roy. Hort. Soc., 34, p. 229 (1908). 



VERMICULARIA (FRIES.) 



Perithecia erumpent or subsuperficial, black, globoso- 

 conical, membranaceo-carbonaceous, at length concave, with 

 a mouth or mouthless, clothed with long, rigid, septate, dark 

 hairs ; conidia usually cylindric-fusoid, often inaequilateral, 

 continuous, borne on variously formed conidiophores. 



In some species the perithecia are imperfect or widely open 

 and JPeztza-like. 



Onion scab (Vermicularia circinans, Berk.) is an erratic 

 parasite, being very abundant during certain seasons, then 

 mysteriously disappearing for a considerable time, and again 

 suddenly appearing in profusion. As a rule but little real 

 injury is done to the bulbs the part attacked; yet the 

 presence of numerous black blotches on the outermost coating 

 much depreciates their sale. 



The fungus usually appears when the bulbs are nearly full 

 grown, under the form of scattered black patches, consisting 

 of minute velvety tufts arranged in concentric circles or wavy 

 lines. I find that the conidia readily infect onions the 

 moment they are mature, the black tufts of spines appearing 

 in about ten to twelve days. It is doubtful as to whether the 

 minute conidia retain their vitality until the following season. 

 Minute black microsclerotia are produced in the tissue of the 

 bulb tunic under diseased spots, and these may probably 

 continue the species in time. It is known that when diseased 

 bulbs are stored along with healthy ones, the disease spreads 



2D 



