56 JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The period from June to August is the important period in any con- 

 sideration of questions relating to plant growth, since it is in this period 

 that the major portion of the rainfall occurs. Reference to the map 

 shows that Sukkur has become the centre of a high-temperature area 

 (above 90° F. average mean temp.). Dera Gazi Khan, Mozuffergarh, and 

 Multan also lie within the area included by this isotherm. Hissar lies 

 just outside this area, Jhind still further outside, while the districts of the 

 Ganges area lie in the easterly directed loop formed by the 85° F. isotherm. 

 The figures inserted after the names of a few stations are sufficient to 

 indicate the general facts as to the distribution of temperature during the 



1 



Fig. 11.— Hissak Plant. 



autumn months, for which period the isotherms are not shown. It is 

 during this period that the crop ripens. Sukkur still remains an area of 

 high temperature (87° F. approx.) ; but throughout the remaining districts 

 the temperature is practically uniform (Multan 77° F., Delhi 76° F., 

 Gorakhpur 77° F.). 



If the normal annual maximum isotherms are considered, the same 

 points are emphasised with perhaps still greater clearness. Sukkur 

 forms a central area with a normal maximum temperature of over 95° F. 

 The Punjaub districts and Hissar lie within the 90° F. isotherm, while 

 the Ganges-valley districts lie between the 90° F. and 85° F. isotherms. 



Sukkur, therefore, stands forward prominently as the area in which 



