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Show If Winter Does Not Come PLANTS need rest and sleep just as other tiring things do, and it is this, and not cold weather, which causes them to become periodically periodi-cally dormant. Intensive Investigations of Dr. Frederick V. Coville of the Federal Department of Agriculture, Agricul-ture, which have been conducted over a period of ten years and which have covered every phasi of the subject, demonstrate that the latter theory is erroneous, says the Scientific American. A certain amount of cold is essential to stimulate stim-ulate the plant growth, despite the old-fashioned idea that retarded growth and low- temperatures arc anonymous. Dr. Coville removed healthy blueberry plants during the late summer from their outdoor beds and placed them in a greenhouse, green-house, where tho plants were maintained at ordinary growing temperatures such as would have kept the plants In luxuriant growth during the spring and summer months. Despite these ideal environments the refractory blueberry plants refused to continue to grow, but instead shed their leaves and shortly lapsed into a condition con-dition of complete dormancy. These practical tests were repeated again and again with many different kinds of plants and without exception all trees and shrubs whlob were natives of northern, cold climates fell asleep in the late fall and early winter Irrespective of tho temperature. Comparative studies of the sus ceptibility of Indoor and outdoor specimens of tho same families of plauts Indicated that dormancy dor-mancy develops a little more quickly in the plants exposed outside, evidently because their foliage is injured by frecalng weather and because be-cause they drop their leaves earlier than do the indoor plants. In fact, unnatural warmth Is a detriment to plant growth. Inasmuch as trees and shrubs that are kept continuously warm during dur-ing the winter take up their ordinary growth much later the following spriug than their mates which arc exposed to a period of chilling and freezing weather. Dr. Coville's detailed tests show that the indoor in-door plants which are not exposed annually to an era of cold weather thereafter will not bloom. |