lo July. 1911-] Abnormal GroivtJis of the Potato. 



44.S 



If now, after a spdl of dry weather and hastened maturity, a fresh 

 rsupply of sap reaches the tubers, or the soil becomes excessively heated, 

 the eyes may begin to grow. 



First, the fresh growth may cause the eyes to shoot, generally at the 

 crown enfl, and this second growth, as it is erroneously called, materially 

 reduces the value of the crop. 



Second, if the tubers have ceased growing and the rain comes coupled 

 with heat, then the potato plant sends a fresh supply of sap into the 

 tubers, causing the eyes to enlarge and swell, so that strings of tubers may 

 be formed as in Figs, i and 3. In this way, the original tuber mav 

 become shrivelled up and its progeny surpass it in size. 



Third, not only may the eyes shoot, or secondary tubers be formed, 

 but the so-called wet ends or snotty ends may be produced. The stem- 

 end of the tuber is stimulated to renewed growth by the sudden and fresh 

 access of water. It becomes gorged, in fact, and enlarges rapidly, so 



3. FHIMARV, SECONDARY, AND TEKIIARY TUBERS. 

 4. SECTION SHOWING BLIGHT IN I, 2, AND 3. 



that a sort of conical end is formed. Being so soft and succulent it is 

 readily bruised, and a kind of f^oft rot is often set ui>. The Vermonts 

 are particularly liable on account of their elongated shape. 



In the normal growth of the potato, single tul>ers are formed at tin- 

 ends or sides of underground branches, but when there is an excess of 

 heat in the soil, the eyes may sprout, irresjx'ctive of moisture; and. i! 

 a fresh growth is set up in the plant, by the necessary heat and n jisture 

 i)eing supi)lie(l after a dry spell, then the eyes or other portions Jl th. 

 plant may enlarge and form tubers direct, giving rise to se<x-)ndarv and 

 tertiary growths. 



An interesting case is shown in l'"igs. 3 and 4 wheri- tlu- primary tulnT 

 has given ri.se to secondary anti tertiary tubers on either side. The 

 spawn or mycelium of the Irish lUight was in the original tuber, and it 



