The smooth and often inclined and waving stem of the tropical grasses exceeds in height our alders and oaks. As far north as Italy, this form already begins, in the _Arundo Donax_, to raise itself from the ground, and to determine, by height as well as mass, the natural character of the country. The form of Ferns[98], like that of grasses, also assumes nobler dimensions in the torrid regions of the earth, and the arborescent ferns, which frequently attain the height of above forty feet, have a palm-like appearance, although their stem is thicker, shorter, and more rough and scaly, than that of the palm. The leaf is more delicate, of a loose and more transparent texture, and sharply serrated on the margins. These colossal ferns belong almost exclusively to the tropics, but there they prefer the temperate localities. As in these latitudes diminution of heat is merely the consequence of an increase of elevation, we may regard mountains that rise 2000 or 3000 feet above the level of the sea as the principal seat of these plants. Arborescent ferns grow in South America, side by side with that beneficent tree whose stem yields the febrifuge bark, and both forms of vegetation are indicative of the happy region where reigns the genial mildness of perpetual spring. I have now to mention the form of the Liliaceous plants[99], _Amaryllis_, _Ixia_, _Gladiolus_, and _Pancratium_, with their flag-like leaves and splendid blossoms, the principal home of which is Southern Africa; also the Willow form[100], which is indigenous in all latitudes, and is represented in the plateaux of Quito, not by the shape of its leaves, but in the form of its ramification, in Schinus Molle; also the Myrtle-form[101] (_Metrosideros_, _Eucalyptus_, _Escallonia myrtelloides_); Melastomaceæ[102]; and the Laurel form[103]. It would be an undertaking worthy of a great artist to study the character of all these vegetable groups, not in hothouses, or from the descriptions of botanists, but on the grand theatre of tropical nature. How interesting and instructive to the landscape painter[104] would be a work that should present to the eye accurate delineations of the sixteen principal forms enumerated, both individually and in collective contrast! What can be more picturesque than the arborescent Ferns, which spread their tender foliage above the Mexican laureloak! what more charming than the aspect of banana-groves, shaded by those lofty grasses, the Guadua and Bamboo! It is peculiarly the privilege of the artist to separate these into groups, and thus the beautiful images of nature, if we may be permitted the simile, resolve themselves beneath his touch, like the written works of man, into a few simple elements.