Note 20 — PHYSIOGNOMY OF PLANTS.

p. 4.—“The Cactus form.”

If we take the natural family of the Opuntiaceæ separated from the Grossulariaceæ (the species of Ribes), and, viewed as it is by Kunth (Handbuch der Botanik, S. 609), we may well regard it as belonging exclusively to America. I am aware that Roxburgh, in the Flora Indica (inedita), cites two species of Cactus as belonging to South Eastern Asia;—Cactus indicus and C. chinensis. Both are widely disseminated, and are found in a wild state (whether they were originally wild or have become so), and are distinct from Cactus opuntia and C. coccinellifer; but it is remarkable that the Indian plant (Cactus indicus) has no ancient Sanscrit name. Cactus chinensis has been introduced in St. Helena as a cultivated plant. Now that a more general interest has at length been awakened on the subject of the original distribution of plants, future investigation will dispel the doubts which have been felt in several quarters respecting the existence of true Asiatic Opuntiaceæ. In the animal kingdom particular forms are found to occur singly. Tapirs were long regarded as a form exclusively characteristic of the New Continent; and yet the American tapir has been found as it were repeated in that of Malacca (Tapirus indicus, Cuv.)

Although the species of Cactus belong, generally speaking, more properly to the tropical regions, yet some are indigenous in the temperate zone, as on the Missouri and in Louisiana, Cactus missuriensis and C. vivipara; and Back saw with astonishment the shores of Rainy Lake, in north lat. 48° 40´, covered with C. opuntia. South of the equator the species of Cactus do not extend beyond the Rio Itata, in lat. 36°, and the Rio Biobio, in lat. 37° 15´. In the part of the Andes which is situated between the tropics, I have seen species of Cactus (C. sepium, C. chlorocarpus, C. bonplandii) growing on elevated plains nine or ten thousand (French) feet (about 9590 and 10660 English) above the level of the sea; but a still more alpine character is shewn in latitudes belonging to the temperate zone, in Chili, by the Opuntia ovallei, which has yellow flowers and a creeping stem. The upper and lower limits beyond which this plant does not extend have been accurately determined by barometric measurement by the learned botanist Claude Gay: it has never been found lower than 6330 French (6746 English) feet, and it reaches and even passes the limits of perpetual snow, having been found on uncovered masses of rock rising from amongst the snows. The last small plants were collected on spots situated 12820 French (13663 English) feet above the level of the sea. (Claudio Gay, Flora Chilensis, 1848, p. 30.) Some species of Echino-cactus are also true alpine plants in Chili. A counterpart to the fine-haired Cactus senilis is found in the thick-wooled Cereus lanatus, called by the natives Piscol, which has handsome red fruit. We found it in Peru, near Guancabamba, when on our journey to the Amazons river. The dimensions of the different kinds of Cactaceæ (a group on which the Prince of Salm-Dyck has been the first to throw great light) offer great variety and contrasts. Echinocactus wislizeni, which is 4 feet high and 7 feet in circumference (4 feet 3 inches and 7 feet 5 inches English), is still only the third in size, being surpassed by E. ingens (Zucc.) and by E. platyceras (Lem.) (Wislizenus, Tour to Northern Mexico, 1848, p. 97.) The Echinocactus stainesii reaches from 2 to 2½ feet diameter; E. visnago, from Mexico, upwards of 4 English feet high, is above 3 English feet diameter, and weighs from 700 to 2000 lbs.: while Cactus nanus, which we found near Sondorillo, in the province of Jaen, is so small that, being only slightly rooted in the sand, it gets between the toes of dogs. The Melocactuses, which are full of juice in the dryest seasons like the Ravenala of Madagascar (forest-leaf in the language of the country, from rave, raven, a leaf, and ala, the Javanese halas, a forest), are vegetable fountains; and the manner in which the horses and mules stamp them open with their hoofs, at the risk of injury from the spines, has been already mentioned (Vol. I p. 19). Since the last quarter of a century Cactus opuntia has extended itself in a remarkable manner into Northern Africa, Syria, Greece, and the whole of the South of Europe; even penetrating, in Africa, from the coasts far into the interior of the country, and associating itself with the indigenous plants.

When one has been accustomed to see Cactuses only in our hothouses, one is astonished at the degree of density and hardness which the ligneous fibres attain in old cactus stems. The Indians know that cactus wood is incorruptible, and excellent for oars and for the thresholds of doors. There is hardly anything in vegetable physiognomy which makes so singular and ineffaceable an impression on a newly arrived person, as the sight of an arid plain thickly covered, like those near Cumana, New Barcelona, and Coro, and in the province of Jaen de Bracamoros, with columnar and candelabra-like divided cactus stems.