PLANT LIFE IN WINTER. It would seem that the freezing point of the sap—the blood in a sense—of a tree or plant may not be really frozen without destroying the life, or at least severely injuring its vitality. So different plants have different freezing points, that is, the degree of cold that will dektroy one class of plants, will not injure others. For instance, a white frost will kill sweet potato, egg plant, and various other tender natives of the tropics, while corn semi-tropical plant—resists a greater degree of cold. Celery will survive until the thermometer sinks to fifteen degrees Fahren heit. Cabbage and other plants of the brassica tribe have their freezing point still lower, while many of our conifera remain active during our severest winters. It is more than probable that the active principle iu the sap may not be frozen without killing the tree, and that ing the fact that the sap of our deciduous trees seems frozen in the winter, the circulation goes on to a greater or less extent. Certainly it does in our cone-bearing trees, or evergreens, as they are generally termed. A very popular error is the helief that evergreens hold their leaves sistently. This, however, is not the case. The so-called evergreens of the North—we are now speaking of true leaved plants—as the holly, ivy, laurel, etc., change their leaves as do the strictly deciduous trees, that is, the mature leaves _drop off, and are replaced with others, but this change is made gradually, and the replacement goes on as the mature leaves are lost. So the tree is never without leaves. The conifera, on the other hand, hold their leaves persistently, some of them for two or more years. Once tney fall they are never replaced by foliage in the place where lost. In these plants leaf buds do not push except from the extremity of the branches. Consequently if the leading branch of such a tree is destroyed, it never thereafter increases in height unless some branch turns upward and again forms the leader. Some of our forest trees ripen their seeds in the winter. This is notably true of some of the cone-bearing These trees are positively ive with the thermometer far below the freezing point. A half active circulation goes ward at all times, just as it does with bybernating mals. During mild spells in winter, this circulation comes easily apparent, as may be shown by chipping the wood. The sap will ately exude, and this is by no means confined to the green species. It is known
to take place with many of our deciduous varieties, the ples being notable examples of this kind. This circulation is in fact necessary to support and mature the buds. If the buds are killed, then indeed active circulation ceases, and the plant dies. All perennial plants, therefore, have a mer medium and a winter medium of activity. tion is going on to a greater or less extent, constantly through the huds, and the green faces of the bark, and this activity is entirely governed by the degree of heat. Thus' a season of mild in winter will cause such activity in the sap, that the buds will sometimes break into leaf. If we carefully sect and examine one of these, even when ently dormant and inactive, we shall find it to be composed either of the blossom or blossoms, or else of a cluster of true leaves, exactly folded and compressed together—and in the smallest possible space—and air and water tight, so far as outward influences are concerned; the outer layers being covered either by a system of hairs, or else with a resinous or glutinous secretion, which resists the direct action of water. All living trees, therefore, have their summer and their winter foliage. The buds that are now maturing to develop into full foliage next spring and summer, were started early last spring, and have been the growth of the whole summer and autumn. During the season of active growth of the tree, or in late spring and summer, but little sap is needed for their growth. The demands of the leaves and the other portions of the plants aro then almost supreme. They, however, come on slowly, and as the summer wanes and autumn comes on, and as the leaves become mature, the sap is diverted more strongly to the buds, until at last they are perfected. These germs contain the future glory and beauty of blossom, foliage, growth and fruit of the coming year. Thus when we speak of trees or plants being bare of foliage during winter, we mean only relatively. Growth is constantly going on while the tree lives, though to the superficial observer it may not be apparent. The winter foliage requires but little nutrition, it is true. It requires protection during the inclement season; this the envelopes afford, holding life intact until the advancing sun of the succeeding spring again calls the full pow ers of the tree or plant into renewed activity,