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DISEASES. 



Gangrene of the Tubers. — This putrefaction 

 of the dahlia tubers, like that which of late years has 

 appeared more generally in those of the potato, ap- 

 pears to be occasioned by unnatural treatment ; such 

 as sudden transition from extreme dryness to moist- 

 ness, from high to lower temperatures, &c. ; for it 

 afflicts, chiefly, those tubers which have, been kept dry 

 through the winter, and are removed to the open soil 

 in the spring ; that have been preternaturally forced 

 to emit shoots, and then are committed to the natural 

 soil and temperatures of our climate. The obvious 

 remedy is more natural treatment. 



Instead of keeping the tubers throughout the 

 winter dry, and freely exposed to the air, let them be 

 stored in sand or earth gently moist ; or let them re- 

 main under an extra depth — about a foot — of soil in 

 the borders where grown.* 



Running, or Variableness of Colour. — Dahlias, like 

 many other flowers, are subject to this mutability or 

 uncertainty of colour, and which, in some, is so strik- 

 ing as to have given rise to their specific names. 

 Gladiolus versicolor and Hibiscus mutabilis are very 

 notable examples of this protean quality. 



* This subject is more fully discussed in the first volume of 

 this series, " The Potato; its Culture, &c." 



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