Growth, Reproduction, and Maturity of Tobacco. 729 



ainouiit of (laylig'ht they may be exposed to as compared to the 

 optimum requirements of that species or variety. 



Auuuals, biennials, and perennials may also he the results ot 

 seasonal rang*e of daylig-ht, as many species are, in a measure, 

 governed by lengtli of daylight rather than the retarding influence 

 of winter. Tlierefore, certain annuals may complete two cycles of 

 reproduction in a single season by subjecting the jolants to a suitable 

 lengtli of daylight or artificial light. Similarly, under certain reduced 

 light exposures, some annuals behave like non-flowering perennials. 



Apparently- the rate of growth is directly proportionate to the 

 length of daily light exposure. 



From the above one would conclude that the proper time for 

 seeding in order to get the correct amount of sunlight is important, 

 and that the seasonal range of daylight is an important factor in con- 

 trolling the natural distribution of plants. 



TemjJerature and Moisture. — The various factors mentioned pre- 

 viously ai'e so vitally dependent one upon the other that it is important 

 to bear in mind that one of these factors, such as temperature, will 

 not give results approaching perfection without the other conditions 

 being favourable to the production of the crop. Tobacco is a plant 

 which is very sensitive to its surroundings, and we must not expect 

 a good development if the conditions under which we compel the plant 

 to grow are unfavourable. To obtain the fullest development in 

 growth the plant requires a humid atmosphere and a fairly high tem- 

 perature, though in my opinion it attains its greatest perfection in 

 temperate zone heat. It lias, however, been very clearly demon- 

 strated that certain varieties or types of tobacco will make good 

 development under the influence of high temperature, while others 

 show poor development. A notable example of this is found in the 

 White Burley types. They seem to reach the highest degree of 

 jjerfection in the Blue Grass Region of Kentucky; there is, however, 

 another factor which plays a vital part in this connection which will 

 be mentioned later. White Burley tobacco, when planted in this 

 country, with occasional exceptions, seems to become somewhat 

 dwarfed, and the different individuals show a Lick of uniformity in 

 their growth, and not infrequently the leaves show a parched or dried 

 condition during the growing period. It seems to thrive best in rather 

 a humid atmosphere and with a moderate temperature. 



Cigar wrapper tobacco, which is probably the most highly 

 specialized type grown, seems to thrive best and, reach the highest 

 degree of perfection in growth, flavour, and aroma, in a high tempera- 

 ture with a fair amount of humidity. During the curing or drying 

 stage, to obtain the best results, the tobacco planter must use his best 

 judgment in this process, as the method of handling- his crop depends 

 largely on the type of tobacco he is attempting- to produce. For 

 example, in the production of cigar wrappers the curing process is 

 an alternating one, in which the tobacco should partially dry during 

 the day and at night it should absorb a certain amount of moisture — 

 this process is called " running," i.e. the cured portion of the tobacco 

 gradually changes from a yellow or green colour to a light mahogany 

 brown. In the production of so-called Virginian tobacco the process 

 is somewhat different; to secure the greatest amount of light-coloured 

 leaf the planter must for the first few days during the yellowing 

 l)rocess prevent curing, by kee])ing the atmosphere liumid, till the 



