About six months ago a branch was taken from a Sempervivum villosum and thrown aside as useless; but instead of withering like most branches that are treated in a similar manner, it continued its greenness nearly as much as the plant from which it was taken. In order to try how long it would live without earth or water it was hung up in a greenhouse head downwards, but still it would not die. We are often told that cats have nine lives, but this Sempervivum appears to have ninety and nine, for every shoot carved beautifully upwards, and had some resemblance to a chandelier in miniature. In the spring of the year the shoots threw up flower-stalks, and for two months past there has been an abundance of flowers, but how long they will continue I cannot tell. From this simple affair I began to think of revolutions in some departments of gardening, which might be of as great importance to some of your readers as Armstrongs gun in modern warfare. Only think of Sempervivum gardens - plants living and flowering without pots, earth, or water.

Both inside and outside of windows may yet be greatly adorned in such a way, and Wardian cases with their misty atmosphere may yet be turned to the left; and a great boon it will be to housekeepers and housemaids, and a saving to carpets and crumcloths, where window gardening can be accomplished without earth or water. A pleasure it will be to many to look upon growing plants in flower, placed in a bouquet stand, or hanging in any convenient place, and not any of the dried and dyed "Immortelles " either, but real living productions. Others might be added to the list. There are the Sedums or Stonecrops, so tenacious of life that they can scarcely be kept from growing in a hortus siccus; and there is the Sempervivum tectorum: the flowers of this well-known plant are no less beautiful than they are curious in their structure, and the plant is so difficult to kill, that it almost requires cooking before it can be well dried; and if the moun tains of herbariums that have accumulated in and about London were turned over, there may be found some plants trying to make their escape from their long confinement that may yet adorn the windows of the metropolis.

Those of your readers who have plenty of plants belonging to Crassnlacese and Ficoidem may try some of them, and observe how long they will endure hanging before they die. I may observe the Sempervivum villosum growing in a pot in the greenhouse has not flowered this season, although growing and healthy enough, while the branch taken from it and hung up by the heels has flowered abundantly. P. Mackenzie.

The first number of the third volume of Sir Wm, Hookers valuable "Species Filicum"

(Pamplin) baa appeared. Another number, "to be published shortly," will complete the volume. That before us is entirely occupied by Lomaria and Blechnum, and has some excellent figures from the hand of Mr. Wm. Wilson.

Also the 10th livraison of Mr. WeddelTs admirable "Chloris andina," with figures by Riocreux, who, if possible, excels himself. This Part begins with Asclepiadeae and ends with Polemoniaceae.

The second Part of " Mr. Custis's Farm Insects "(Blackie & Son) is chiefly occupied by the enemies of the turnip crop.

Of "Le Jardin Fruitier de Museum," by M. Decaisne, Parts 22, 23, and 24, No. 22 is occupied by the Princess Royale and Sir Harry strawberries; 23 by the Marquise, Fondaote des Bois, Epergne, and Bassin pears; 24 by Mouille Bouche (one of the sorts called Verte longue), and Jalousie pears, and the Washington and Royale de Tours Plums.