Origin of Cultivated Plants. Alphonse de Candolle

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СКАЧАТЬ examination might lead us to share the opinion of Meyer,164 who distinguished the Asiatic plant from the American species. However, this author has not been generally followed, and I suspect that if there is a different Asiatic species it is not, as Meyer believed, the sweet potato described by Rumphius, which the latter says was brought from America, but the Indian plant of Roxburgh.

      Sweet potatoes are grown in Africa; but either the cultivation is rare, or the species are different. Robert Brown165 says that the traveller Lockhardt had not seen the sweet potato of whose cultivation the Portuguese missionaries make mention. Thonning166 does not name it. Vogel brought back a species cultivated on the western coast, which is certainly, according to the authors of the Flora Nigritiana, Batatas paniculata of Choisy. It was, therefore, a plant cultivated for ornament or for medicinal purposes, for its root is purgative.167 It might be supposed that in certain countries in the old or new world Ipomœa tuberosa. L., had been confounded with the sweet potato; but Sloane168 tells us that its enormous roots are not eatable.169

      Ipomœa mammosa, Choisy (Convolvulus mammosus, Loureiro; Batata mammosa, Rumphius), is a Convolvulaceous plant with an edible root, which may well be confounded with the sweet potato, but whose botanical character is nevertheless distinct. This species grows wild near Amboyna (Rumphius), where it is also cultivated. It is prized in Cochin-China.

      As for the sweet potato (Batatas edulis), no botanist, as far as I know, has asserted that he found it wild himself, either in India or America.170 Clusius171 affirms upon hearsay that it grows wild in the new world and in the neighbouring islands.

      In spite of the probability of an American origin, there remains, as we have seen, much that is unknown or uncertain touching the original home and the transport of this species, which is a valuable one in hot countries. Whether it was a native of the new or of the old world, it is difficult to explain its transportation from America to China at the beginning of our era, and to the South Sea Islands at an early epoch, or from Asia and from Australia to America at a time sufficiently remote for its cultivation to have been early diffused from the Southern States to Brazil and Chili. We must assume a prehistoric communication between Asia and America, or adopt another hypothesis, which is not inapplicable to the present case. The order Convolvulaceæ is one of those rare families of dicotyledons in which certain species have a widely extended area, extending even to distant continents.172 A species which can at the present day endure the different climates of Virginia and Japan may well have existed further north before the epoch of the great extension of glaciers in our hemisphere, and prehistoric men may have transported it southward when the climatic conditions altered. According to this hypothesis, cultivation alone preserved the species, unless it is at last discovered in some spot in its ancient habitation – in Mexico or Columbia, for instance.173

      Beetroot—Beta vulgaris and B. maritima, Linnæus; Beta vulgaris, Moquin.

      This plant is cultivated sometimes for its fleshy root (red beet), sometimes for its leaves, which are used as a vegetable (white beet), but botanists are generally agreed in not dividing the species. It is known from other examples that plants slender rooted by nature easily become fleshy rooted from the effects of soil or cultivation.

      The slender-rooted variety grows wild in sandy soil, and especially near the sea in the Canary Isles, and all along the coasts of the Mediterranean Sea, and as far as the Caspian Sea, Persia, and Babylon,174 perhaps even as far as the west of India, whence a specimen was brought by Jaquemont, although it is not certain that it was growing wild. Roxburgh’s Indian flora, and Aitchison’s more recent flora of the Punjab and of the Sindh, only mention the plant as a cultivated species.

      It has no Sanskrit name,175 whence it may be inferred that the Aryans had not brought it from western temperate Asia, where it exists. The nations of Aryan race who had previously migrated into Europe probably did not cultivate it, for I find no name common to the Indo-European languages. The ancient Greeks, who used the leaves and roots, called the species teutlion;176 the Romans, beta. Heldreich177 gives also the ancient Greek name sevkle, or sfekelie which resembles the Arab name selg, silq,178 among the Nabatheans. The Arab name has passed into the Portuguese selga. No Hebrew name is known. Everything shows that its cultivation does not date from more than three or four centuries before the Christian era.

      The red and white roots were known to the ancients, but the number of varieties has greatly increased in modern times, especially since the beetroot has been cultivated on a large scale for the food of cattle and for the production of sugar. It is one of the plants most easily improved by selection, as the experiments of Vilmorin have proved.179

      Manioc—Manihot utilissima, Pohl; Jatropha manihot, Linnæus.

      The manioc is a shrub belonging to the Euphorbia family, of which several roots swell in their first year; they take the form of an irregular ellipse, and contain a fecula (tapioca) with a more or less poisonous juice.

      It is commonly cultivated in the equatorial or tropical regions, especially in America from Brazil to the West Indies. In Africa the cultivation is less general, and seems to be more recent. In certain Asiatic colonies it is decidedly of modern introduction. It is propagated by budding.

      Botanists are divided in opinion whether the innumerable varieties of manioc should be regarded as forming one, two, or several different species. Pohl180 admitted several besides his Manihot utilissima, and Dr. Müller,181 in his monograph on the Euphorbiaceæ, places the variety aipi in an allied species, M. palmata, a plant cultivated with the others in Brazil, and of which the root is not poisonous. This last character is not so distinct as might be believed from certain books and even from the assertions of the natives. Dr. Sagot,182 who has compared a dozen varieties of manioc cultivated at Cayenne, says expressly, “There are maniocs more poisonous than others, but I doubt whether any are entirely free from noxious principles.”

      It is possible to account for these singular differences of properties in very similar plants by the example of the potato. The Manihot and Solanum tuberosum both belong to suspected families (Euphorbiaceæ and Solanaceæ). Several of their species are poisonous in some of their organs; but the fecula, wherever it is found, is never harmful, and the same holds good of the cellular tissue, freed from all deposit; that is to say, reduced to cellulose. In the preparation of cassava, or manioc flour, great care is taken to scrape the outer skin of the root, then to pound or crush the fleshy part so as to express the more or less poisonous juice, and finally the paste is submitted to a baking which expels the volatile parts.183 Tapioca is the pure fecula without the mixture of the tissues which still exist in the cassava. In the potato the outer pellicle contracts noxious qualities when it is allowed to become green by exposure to the light, and it is well known that unripe or diseased tubers, containing too small a proportion of fecula with much sap, are not good to eat, and would cause positive harm to persons who consumed any quantity of СКАЧАТЬ