.i()4 EXPERIMENT STATION RECORD. 



nilliiiji IVom their pedicles Avhen attacked, and as in tlie case of the 

 leaves, only the lower flowers and grapes are affected. 



The disease is found on vineyards on light soils or in granite, slaty, 

 or pebbly ones, in fact in any soil sensible to climatic changes. Those 

 vineyards suffered most which were most affected by the extreme 

 drought of l.Si»;{, which ended in April, 1894, by continual rains, caus- 

 ing a remarkable fall in the temperature of the air and soil, and result- 

 ing in a marked change in the vegetative condition of the vines. 

 Kecently vineyards on compact soil have been noticed that were con- 

 siderably affected. The authors think the disease due to these meteoro- 

 logical conditions, and French stock seems most subject to its attacks. 



The point of attack on the leaves seems to be at the union 

 of the petiole and leaf blade. If sections be made through a 

 petiole at the point of attack and examined there will be seen isolated 

 cells, fragments of vessels, and crystals and raphides of oxalate of lime 

 in abundance. Some of the cell walls are as thin as ordinary paren- 

 chyma; others are irregularly thickened, white, and glistening like col- 

 lenchyma. They preserve their form, but their protoplasmic contents 

 are changed and large vacuoles are abundant. The middle lamella, by 

 which the cells should be united, is completely wanting, and a slight 

 jar will cause the leaf blade to fall. It may be that in place of the cel- 

 lulose of the middle lamella a pectate of lime is forined, and for this 

 reason the name pectic disease is given. Practically the same condi- 

 tions are to be found in the veins and other parts of the diseased leaves 

 as just described for the petiole. 



The same phenomena may be observed in the case of the fruit as in 

 the leaves, and no parasite of any kind is ever associated with the 

 disease. The disease is attributed to abnormal conditions under which 

 the plants grew, and whatever tended to restore the nornml luitrition 

 of the vines checked the disease. 



The perithecia of white rot of grapes, 1'. A'iala and L. IIavaz 

 {Compt. Rend, 119 (l-'^O^), No. S, pp. 143, 411).— The i^ycukUixl form of 

 this fungus, known as Coniotlnjriinn diplodleUa, has been known since 

 1885, but the irniting form was not known until it was discovered by 

 the authors in ISIK}. By confining infested stems, peduncles, and 

 branches and their attached organs in sterilized sand and controlling 

 the atmosphere and moisture the perithecia can be obtained. They 

 are spherical, 140 to 150/< in diameter; their envelope is multicellular, 

 very black, with a large crateriform opening. The paraphyses are fili- 

 form, regular, white, rarely branching above, and usually longer than 

 the asci. The asci are ,")();.< long by 8.5/^ in diameter, with a thin pearly 

 membrane. They are borne on a weak stalk one sixth their height. 

 The spores are 3.75 by 15/^, 8 to each ascus, fusiform, slightly curved, 

 hyaline, or slightly tinted with yellow when ripe. The spores show a 

 number of partitions, often varying in the same ascus. They are 

 double or may be four-celled walls, the middle always being the 

 thickest. 



