xviii.] EAR-COCKLE IN WHEAT, OATS, & RYE. Ill 



sented by mere minute swellings on the little lateral axis 

 destined to produce the spikelet. 



The small worm, we suppose, attacks these swellings 

 either the one belonging to the pistil, the three belonging 

 to the stamens, or the two belonging to the scales. The 

 parts attacked may, however, belong in part to more than 

 one series, as one scale and one stamen, or the pistil and 

 one scale, etc. When the puncture is made, an unusual 

 flow of sap to the injured place possibly a natural attempt 

 to repair the injury is the result, an extremely common 

 phenomenon in plant injuries. This flow of sap causes 

 the first cells of the monstrous gall-growth to appear : 

 the abnormal growth is rapid in development, and in a 

 short time the assailing Nematode or Nematodes are en- 

 closed within an abnormally-grown cell wall. A section 

 of a mature gall is shown at Fig. 45, C, and a section 

 farther enlarged to forty diameters is shown at Fig. 46, 

 illustrating part of the wall and part of the enclosed 

 colony of Nematodes. Both sections show the compara- 

 tively thick nature of the wall of the gall, and the large 

 number of thick obscurely hexagonal cells of which it is 

 built up. It is remarkable that the fungus of corn mildew 

 and other fungi peculiar to corn have been seen growing 

 upon these galls. The fact probably shows how completely 

 the substance of the galls agrees in nature with the sub- 

 stance of the wheat plant from which they are derived. 



When a young gall is cut in two and its interior ex- 

 amined, it is found filled with a cottony mass, which, on 

 enlargement with the microscope, becomes revealed as a 

 mass of semi-transparent nematoid worms of all sizes, 

 from mature individuals one -seventh of an inch long, 

 through semi-mature and infant individuals, to transparent 

 eggs, in which the little Nematodes may be seen coiled up. 

 A group of these worms, in all stages of growth, may be 

 seen at A, Fig. 46, drawn to the same scale, i.e. enlarged 

 forty diameters, as the adjoining wall of the gall at B. 

 By the time the gall is quite mature the mother worms 



