Grasses and Grains 13 to 15 days. Raspberry, Strawberry, Cherry 2 months. Bird-cherry, Lime-tree 3 months. Roses, White Thorn, Horsechestnut 4 months. Vine, Pear, Apple, Walnut, Beech, Plum, Nut, Almond 5 to 6 months. Olive, Savin 7 months. Colchicum, Mistletoe 8 to 9 months. Coniferæ 10 to 12 months. Some Coniferæ, certain Oaks, and Metrosideros above 12 months. "The ripening of fruits may be accelerated by the application of heat, the placing of dark-colored bricks below it, and by removing a ring of bark, so as to lead to an accumulation of sap. It has been observed that plants, subjected to a high temperature, not unfrequently prove abortive; this seems to result from the over stimulation, causing the production of uni-sexual flowers alone. Trees are sometimes made to produce fruit by checking their roots when too luxuriant, and by preventing the excessive development of branches."[22] Here we have the explanation of the processes of root pruning and of summer pinching, and shortening-in, which have been more extensively introduced upon another page; as well as the plan for inducing fruitfulness in such trees as are tardy from excessive wood-growth, by hacking the bark to interrupt the flow of sap from the buds to the roots; by this, some of the former are changed to flower-buds.