Firs and pines, existing in vast numbers, and retaining a perpetual though gloomy verdure, characterize the transition from the frigid to the northern temperate zone. This last extends from the parallels of 50 deg. to 40 deg. north latitude, and in its southern borders, the beech, the lime, and the chestnut, mingle with the trees peculiar to more southern regions. The meadows and pastures, especially those in the vicinity of the sea and in the mountain-valleys, are clothed with a brilliant verdure, which we in vain look for in the other sections of the globe. The warm temperate zone, extending to 25 deg., presents in general a less beautiful vegetation; for although the heat is greater the humidity is less constant. But it is in the torrid latitudes that Nature displays all her magnificence. There the species of tribes, which in other climates are herbaceous, become shrubs, and the shrubs trees. Ferns rise into trunks equal to those of pines in the northern regions of Europe; balsams, gums, and resins, exude from the bark; aromatic fruits and flowers abound; and the savage, as he roams the woods, satisfies his hunger with the spontaneous offerings of the soil. Here also are all the climates of the globe, and almost all their productions united; for, while the plains are covered with the gorgeous vegetation of the tropics, the lofty mountains display the forms that occur in the colder regions, and the places intermediate in elevation all the graduated transitions from these to the warmest parallels. The vegetation of the seas presents much less diversity than that of the land. It is less luxuriant, less elegant, less ornamented, and less productive of substances directly useful to man. There is also less distinction between marine plants of different latitudes; for the great currents of the ocean, and other causes, render its temperature more equable than that of the atmosphere. The numerous and diversified forms which plants assume, their distribution over the globe, their various qualities and uses, and their internal organization, are subjects which have long occupied the attention of observers. In their reproduction, growth, and maturation, phenomena are presented to us, which are well calculated to excite our admiration; and the curious and diversified apparatus of tubes and cells, in which are circulated the fluids derived from the atmosphere and the earth, although apparently more simple than that of the animal economy, affords a profound as well as an interesting subject of research.