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EXPLANATION OF PLATES. 



Plate I. Fig. 1. — A field of ordinary upland cotton at Dillon, S. C, showing 

 the damage caused by the wilt disease (photographed in August. 

 1900). Fig. 2. — Field of healthy upland cotton adjoining the in- 

 fected field shown in fig. 1 (piiotographed in August, 1900). 



Plate II. Comparative resistance to wilt disease of different races of cotton in 

 experimental plots of Division of Vegetable Physiology and Pathol- 

 ogy, on the farm of Mr. H. L. Galloway, at Dillon, S. C. (photo- 



graphed August, 1900) : 



Fig. 



1. — Jannovitch, an Egyptian cotton, on 



the left, and King, a common upland race, on the right. Fig. 

 2. — Jackson, on the left, and Drake, on the right. These plots were 

 planted at the same time and treated exactly alike. 



Plate III. Fig. 1. — Root tufts produced by partial infection of resistant plants. 

 The roots figured here were from a jjlant of Jannovitch c tton taken 

 from the row shown in PI. II. fig. 1. There were about one hundred 

 and fifty of these little tufts on this root. (Drawn by Mr. W. R. Scholl, 

 from a root collected in September, 1900. ) Fig. 2. — Egyptian cotton 

 plants, showing the dwarfing effect of numerous partial infections 

 of the small roots. The plant at the left came from noninfected soil 

 and is healthy, while that at the right grew on infected land near 

 by. (Drawn by Mr. W. R. Scholl. from a photograph.) 



Plate IV. Sea island cotton resistant to the wilt disease {photographed Septem- 

 ber, 1900, on the plantation of Mr. Elias L. Rivers, James Island, 

 S.C). The row in the foreground was planted with seed from a 

 single healthy plant that grew in infected land the year before. 

 The adjoining rows, now almost entirely killed by the wilt disease, 

 were planted with seed of the ordinary, fine sea island cotton. 

 There are a few scattered plants in these rows that have resisted the 

 disease. It was from such a plant as these that the seeds planted in 

 the middle row were taken. 



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