disguise, covered only by a soft, sweet pulp that entices animals to aid in dispersing them, by dropping the hard seed on to the ground in favorable spots for its growth. In temperate climates the stones are only hard enough to defy squirrels and birds: in tropical countries they are hard enough to defy monkeys and parrots. Compare, for example, the English sloe or bird-cherry with the peach-stone, and the English haw with the mango or vegetable ivory. This last nut is one of the oddest in the whole range of nature, for it is here the actual kernel itself that grows so hard and horny. Yet even the vegetable ivory, which consists really of very solid starchy cells, softens and yields up its material to the growing plant as soon as the embryo it incloses begins to sprout under the influence of warmth and moisture. THE CACTUS TRIBE --M. J. SCHLEIDEN Let us leave the forest of Guiana, the last mat-roof of the Guaranese between the trunks of the Mauritius palm, and enter the pampas of Venezuela, of which Humboldt has sketched such a clever and vivid picture. No smiling verdure clothes the glowing rock-soil here; here and there in its crevices the Melocactus displays its round balls, “horrid” with threatening thorns. Ascend we thence the Andes; instead of tender grass, the earth is covered with pale, gray-green globes of spiny Mamillarias, while, intermingled, rises the solemn and mournful old-man cactus, with its venerable-looking long gray hair. Borne on the wings of fancy further north, we descend into the plains of Mexico, where the gigantic fragments of the city of the Aztecs, a product of a solitary era of civilization long lost to history, display themselves; the landscape spreads out before us as the bare and naked Tierra caliente, parched by the glowing sun; of a dull green hue, without a branch or leaf, the angled-columns of the torch-thistles rise twenty or thirty feet high, hemmed in with an impenetrable thicket of irritably pricking Indian figs, while round about appear the strangest, ugliest forms, in the groups of the Echinocacti and little Cerei, between which creeps snake-like, or as some great poisonous reptile, the long, dry stem of the great flowered cactus (Cereus nycticallus). In short, one family accompanies us through all our wanderings, that of the cactus plants, which seems in all its wondrous forms to withdraw itself entirely from the principle of beauty, and yet at the same time presses forward so strikingly, so determinately marking the peculiar character of the landscape, that we are compelled to turn our attention to it. And in truth, a group which appears to retreat so far from all the laws of other plants deserves our interest in a very high degree.