Note 96 — IDEAS FOR A PHYSIOGNOMY OF PLANTS.

p. 228—“The form of Aloes.”

To this group of plants, which is characterised by a great similarity, belong Yucca aloifolia, which penetrates as far north as Florida and South Carolina; Y. angustifolia (Nutt.), which advances to the banks of the Missouri; Aletris arborea; the Dragon-tree of the Canaries, and two other Dracænas belonging to New Zealand; arborescent Euphorbias; and Aloe dichotoma, Linn., (formerly the genus Rhipidodendrum of Willdenow), the celebrated Koker-boom, whose stem is four feet in thickness, about twenty feet high, and has a crown measuring 426 feet round.^[QE] The forms which I have 333here associated together belong to very different families: as, for instance, to the Liliaceæ, Asphodeleæ, Pandaneæ, Amaryllideæ, and Euphorbiaceæ; and are therefore, with the exception of the last named, all included under the great division of Monocotyledons. One of the Pandaneæ, Phytelephas macrocarpa (Ruiz), which we found on the banks of the Magdalena river in New Granada, exactly resembles with its feathery leaves a small palm-tree. The Tagua (as it is called by the Indians) is moreover, as Kunth has observed, the only Pandanea of the New Continent. The singular Agave-like and high-stemmed Doryanthes excelsa of New South Wales, which the intelligent Correa de Serra was the first to describe, belongs to the Amaryllideæ, like our low-growing Narcissuses and Jonquils.

In the candelabra-like form of Aloes, the branches of the main-trunk must not be confounded with the flower-stalks. In the American aloe, Agave Americana (Maguey de Cocuyza), which is entirely wanting in Chili, and in the Yucca acaulis (Maguey de Cocuyza), the leaf-stalks present a candelabra-like arrangement of the blossoms during the excessively rapid and gigantic development of the inflorescence, which, as is well known, is but too transient a phenomenon. In some arborescent Euphorbias the physiognomical character depends, however, on the branches and their arrangement. Lichtenstein describes,^[QF] with much animation, the impression made upon him by the appearance of an Euphorbia officinarum which he saw in the “Chamtoos Rivier,” near Cape Town. The form of the tree was so symmetrical, that it repeated itself on a small scale, like a candelabrum, to a height of more than 30 feet. All the branches were furnished with sharp thorns.

Palms, Yucca and Aloe plants, arborescent Ferns, some Aralias, and the Theophrasta, where I have seen it in a state of luxuriant growth, present to the eye a certain physiognomical resemblance of character by the nakedness of the stems (there being no branches) and the beauty of their summits or crowns, however they may otherwise differ in the structure of the inflorescence.

Melanoselinum decipiens, (Hofm.), which has been introduced into our gardens from Madeira, and is sometimes from 10 to 12 feet high, belongs to a peculiar group of 334arborescent umbelliferæ allied to the Araliaceæ, to which other species, as yet undiscovered, will undoubtedly at some future time be added. Ferula, Heracleum, and Thapsia likewise attain a considerable height, but they are still herbaceous shrubs. Melanoselinum stands almost entirely alone as an arborescent umbelliferous plant; Bupleurum (Tenoria) fruticosum, Linn., of the shores of the Mediterranean, Bubon galbanum of the Cape, and Crithmum maritimum of our sea-coasts, are only shrubs. Tropical countries, where, as Adanson long since very correctly remarked, Umbellifereæ and Crucifereæ are almost wholly wanting in the plains, exhibit, as we ourselves observed, the most dwarfish of all the umbelliferous family on the lofty mountain ridges of the South American and Mexican Andes. Among the thirty-eight species which we collected on elevations whose mean temperature was below 54°.5 Fahr., we found Myrrhis andicola, Fragosa arctioïdes, and Pectophytum pedunculare, interspersed with an equally dwarfish Alpine Draba, growing moss-like close to the rock and the frequently frozen earth, at a height of 13,428 feet above the level of the sea. The only tropical umbelliferous plants which we found on the plain in the New Continent were two species of Hydrocotyle (H. umbellata and H. leptostachya) between the Havannah and Batabano, and therefore at the extreme limit of the torrid zone.