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Show Effect of Light on . Flowers and Plants Spring violets have been made to bloom In the summer simply by cut- j ting down their ration of daylight to J the length of a spring day. The extra heat of summer hud no effect on the growth of the plant. In this controlling of plant growth, artificial light has the same effect as sunlight or the light of a greenhouse, j and twelve hours of light (whether natural or artificial) la "summertime" for the plants, and six hours' light "winter;" An experiment conducted with Irises j Is given as nn example of the effect j of UglTt rationing on plunts. Two lots of irises were sown in lute October; 1 the first were given eighteen hours of light per day, while the ofhers (kept In the same temperature) received only the light provided by nature. The first lot reached normal size very quickly, and actually bloomed on Christmas day, but the others were ! dormant as late as the following February. Feb-ruary. : |