It is remarkable, that of this majestic form of plants (some of which rise to more than twice the height of the Royal Palace at Berlin, and to which the Indian Amarasinha gave the characteristic appellation of "Kings among the Grasses") up to the time of the death of Linnceus only 15 species were described. The Peruvian travellers Ruiz and Pavon added to these 8 more species. Bonpland and I, in passitfg over a more extensive range of country, from 12° S. lat. to 21° N. lat., described 20 new species of palms, and distinguished as many more, but without being able to obtain complete specimens of their flowers. (Humboldt, de distrib. geogr. Plantarum, pp. 225-233.) At the present time, 44 years after my return from Mexico, there are from the Old and New World, including the East Indian species brought by Griffith, above 440 regularly described species. The Enumeratio Plantarum of my friend Kunth, published in 1841, had already 356 species.
A few, but only a few species of palms, are, like our Conifers.', Quercineae, and Betulineae, social plants; such are the Mauritia flexuosa, and two species of Chamoerops, one of which, the Gha- maerops humilis, occupies extensive tracts of ground near the mouth of the Ebro, and in Valencia; and the other, C. mocini, discovered by us on the Mexican shore of the Pacifie, and entirely without prickles, is also a social plant. While some kinds of palms, including Chamrcrops and Cocos, arc littoral or shore-loving trees, there is in the tropies a peculiar group of mountain palms, which, if I am not mistaken, was entirely unknown previous to my South American travels. Almost all species of the family of palms grow on the plains or low grounds, in a mean temperature of between 22° and 24° Reaumur (81°.5 and 86°, Fahr.); rarely ascending so high as 1900 English feet on the declivities of the Andes: bat in the mountain palms to which I have alluded, the beautiful wax- palm (Ceroxylon andicola), the Palmeto of Azufral at the Pass of Quindiu (Oreodoxa frigida), and the reed-like Kunthia montana (Cana de la Vibora) of Pasto, attain elevations between 6400 and 9600 English feet above the level of the sea, where the thermometer often sinks at night as low as 4°.8 and 6° of Reaumur (42°.8
and 45°.5 Fahr.), and the mean temperature scarcely amounts to 11° Reaumur, or 56°.8 Fahrenheit. These Alpine Palms grow among Nut trees, yew-leaved species of Podocarpus and Oaks (Quercus granatensis). I have determined by exact barometrical measurement the upper and lower limits of the range of the Wax- palm. We first began to find it on the eastern declivity of Andes of Quindiu, at the height of 7440 (about 7930 English) feet above the level of the sea, and it extended upwards as far as the Garita del Paramo and los Voleancitos, or to 9100 (almost 9700 English) feet: several years after my departure from the country, the distinguished botanist Don Jose Caldas, who had been long our companion amidst the mountains of New Grenada, and who afterwards fell a victim to Spanish party hatred, found three species of palms growing in the Paramo de Guanacos very near the limits of perpetual snow; therefore, probably at an elevation of more than 13,000 (13,855 English) feet. (Semanario de Santa Fe de Bogota, 1809, No. 21, p. 163.) Even beyond the tropies, in the latitude of 28° north, the Chamaerops martiana reaches on the sub-Himalayan mountains a height of 5000 English feet. (Wallich, Plantae Asia- ticae, vol. iii. tab. 211.)
If we look for the extreme geographical limits of palms (which are also the extreme climatic limits in all the species which inhabit localities but little raised above the level of the sea), we see some, as the date-palm, the Chamaerops humilis, C. palmetto, and the Areca sapida of New Zealand, advance far into the temperate zones of either hemisphere, into regions where the mean temperature of the year hardly equals 11°.2 and 12°.5 Reaumur (57°.2, and 60°.2 Fahrenheit). If we form a series of cultivated plants or trees, placed in order of succession according to the degree of heat they require, and beginning with the maximum, we haw Cacao, Indigo, Plantains, Coffee, Cotton, Date-palms, Orange and Lemon Trees, Olives, Sweet Chestnuts, and Vines. In Europe, date-palms (introduced, not indigenous) grow mingled with Chamaerops humilis in the parallels of 43 J° and 44°, as on the Genoese Rivera del Ponente, near Bordighera, between Monaco and San Stefano, where there is an assemblage of more than 4000 palm-stems; and in Dalmatia round Spalatro. It is remarkable that Chamaerops humilis is abundant both at Nice and in Sardinia, and yet is not found in the Island of Corsica, which lies between those localities. In the New Continent, the Chamaerops palmetto, which is sometimes above 40 English feet high, only advances as far north as 34° latitude, a difference sufficiently explained by the inflexions of the isothermal lines. In the Southern Hemisphere, in New Holland, palms, of which there are very few (six or seven species), only advance to 34° of latitude (see Robert Brown's general remarks on the Botany of Terra Australis, p. 45); and in New Zealand, where Sir Joseph Banks first saw an Areca palm, they reach the 38th parallel. Id Africa, which, quite contrary to the ancient and still widely prevailing belief, is poor in species of palms, only one palm, the Hyphaene coriacea, advances to Port Natal in 30° latitude. The Continent of South America presents almost the same limits in respect to latitude. On the eastern side of the Andes, in the Pampas of Buenos Ayres and in the Cis-Plata province, palms extend, according to August* de St-Hilaire, to 34° and 35° S. latitude. This is aim the latitude to which, on the western side of the Andes, the Coco de Chile (our Jubaea spectabilis ?), the only Chilian palm, extends, according to Claude Gay, being as far as the banks of the Rio Maule. (See also Darwin's Journal, edition of 1845, pp. 244 and 256.)
Alexander von Humboldt
Aspects of Nature: In Different Lands and Different Climates; with Scientific Elucidations
Trad. Elizabeth Juliana Leeves Sabine