212 



Continuing, the writer describes and figures a most interesting 

 sport in the " Giant Blue" variety of 5. tuberosum. 



" The aerial tubers are formed in the month of September, but 

 not on the principal stem growing from the seed tuber, nor on 

 its branches, but on two branches arising in the midst of an 

 inflorescence. The flowers, as is the case in all cultivated vane- 

 ties, had fallen without being fertilized, but the peduncles to 

 which they were attached were still green and perfectly distinct. 

 The inflorescences of Solauuvi tubcrosuvi being terminal, it must 

 be admitted that the axes of two of the sterile flowers were pro- 

 longed into leafy branches. These branches are remarkable for 

 their size, much greater than that of the main stem below the 

 inflorescence ; they bear well-developed leaves in the axils of 

 which are shown the tubers. These, one simple, the other 

 branched, are terminated by a tuft of small leaves, and they 

 would have developed branches if I had not cut them off for 

 preservation in alcohol. Leaves are uniformly present over the 

 surface of the tubers below the buds commonly called ' eyes,' 

 and which in two of the tubers represented in the accompanying 

 figure have developed into secondary tubers." The chlorophyll 

 which has formed in the light has masked the blue color of the 

 tubers. 



Labergerie describes the formation of aerial tubers on Solaiium 

 Conimcrsoui. In this case, he says, the moisture of the soil is an 

 important factor in the development of the tubers, but not the 

 cause of their production. They form in the leaf axils, and also 

 at the extremities of rather long branches. The exact conditions 

 under which they develop has not been ascertained, but they 

 seem to be produced under different conditions from those in the 

 case of S. tuberosum. 



C. Stuart Gager. 

 New York Botanical Garden, 

 October 3, 1906. 



