104 



CORN AND GRASS. 



"Ear-cockles"; "Purples"; "False Ergot"; Galls of Wheat 

 Eelworms. Tylenckiis tritkl, Bastian; YiJirio tritici, Bauer. 



Wormlets escaping from eggs ; section of Cockle-gall, with wormlets within ; 

 after Bauer's figs, (much magnified). Spikelet of Wheat, with galls (magnified). 

 T. tritici wormlet (greatly magnified), nat. length of largest about one-fourth 

 inch. 



This paper is placed immediately after that on Tulip-root, 

 as the diseased growths known respectively as Tulip-root, and 

 Ear-cockles, are in each case caused by presence of Eelworms 

 of the genus Tylenchus ; in one case by the T. derastatrix, in 

 the other by the T. tritici. 



Cockle-galls, or " Purples," are the small roundish or 

 distorted growths, sometimes found in Wheat which give an 

 appearance to the ear much as if purplish or dark coloured 

 pei^percorns had taken the place of the Wheat grains. Some- 

 times they are present in great numbers, as in 1886 when a 

 bunch of Wheat almost ruined by the amount of Cockle-galls 

 present was sent me from near Cirencester, with the note 

 that there was presence of this gall attack in Wheat in three 

 fields covering together about twenty-seven acres ; but this 

 amount of infestation appears to be quite exceptional. 



On splitting one of the galls and placing it in a drop of 

 water, the vast number of wormlets within (which were all 

 collected together, as shown in the section of a Cockle-gall 

 figured above magnified) swelled up and overflowed in count- 

 less numbers on the microscope slide. 



The method of spread of attack as quoted by Dr. Charlton 

 Bastian, from M. Davaine's experiments, is that when the 

 infested galls are sown, these galls become softened, and the 

 wormlets within, thus being able to escape, make their way to 

 the young sprouting plants, " and then insert themselves 

 between the sheaths of its leaves, gradually working their way 

 round till they come to the innermost of these, where they 

 remain for a variable time, without increasing much in size, 



