Gardeners' Chronicle Dec. 16, 1848. p. 828.
THE MELLOCO
Louis Vilmorin, Paris, Dec. 7.

IT was with considerable interest that I read, the extract of a letter from M. de Jonghe, of Brussels, on the Melloco (Ullucus tuberosus, Loz.), published in the Gardeners' Chronicle of the 4th of November last. Perhaps the following account. of its introduction and cultivation in France will not be unacceptable to your readers The plant was introduced into France last January by M. C. Ledos, of Lima, who sent some tubers to the Minister of Agriculture and Commerce, by whom they were distributed to a few individuals, of whom 1 was one.

The information sent respecting the tubers was very incomplete, and related almost entirely to their preservation, "which," according to M Ledos, "cannot be  effected for more than three or four months, in a dry fresh place. If the tubers are kept longer than that, the eyes begin to develope ; their growth does not, however, affect the tuber's power of germination. When spring, the time at which the tubers ought to be planted, is arrived, the shoots are taken off, and they themselves serve very well for propagation. So long as the tuber is not completely dried, it remains fit for planting. After the shoots are removed the tubers are left in the sun for a few hours to dry."

The tubers received by me were in a very advanced stage of vegetation; they were withered and exhausted by the long shoots which had grown during the voyage, and which were, in consequence of the moisture of the packing, themselves half rotten. Fearing that in this state they would not keep till the time for planting them in the open air arrived, I planted some under a pitash; this precaution was not necessary, for although I kept. the best tubers for out-door planting, two only of those developed. Luckily the great facility with which this plant can he multiplied by cuttings enabled me to repair this lose, and at the beginning of May I had 40 good plants in vegetation.

*Your figure, p. 685 (1847), if very correct, and gives a much better idea of the plant than the figure in the "Revue Horticole" for the 1st of November.

The Melloco is half a runner; its shoots, without support, send out roots whereever the ground is touched; its leaves are thick and fleshy; from being large and spreading, they become erect and round like a shell, in the fully, developed plant. The flowers, which are small and greenish, spring in spikes from the axil of the leaves.* The earliest flowers expanded in the beginning of June, but they did not set. The floral spikes, which appeared during the summer months were always abortive; at the end of August and in September there was an abundance of flowers, all apparently well constructed. In my opinion the propagation by sowing (when the seeds are taken from plants already growing in the soil) is the best for inuring the plants to our climate, because in this case there is a chance of obtaining varieties, modified by the new conditions of climate to which the sets (plantes mères) are exposed. I thought it very important to procure seeds of Melloco; but although I have several times tried to set the flowers by artificial means, I have never been able to obtain any seed, nor indeed any appearance of a ripe ovary.

The produce of the Melloco consists in its tubers, which, in their native country, attain a considerable size. They are yellow, very smooth, full of starch, and are developed on runners proceeding from the base of the stem, and tending to rise to the surface of the soil; the plant must therefore be pretty well earthed up.

+From the middle of the summer I had foreseen this result, in consequence of some valuable information given me by M. Boussingault respecting the atmosphere and temperature of the table lands of the Andes. He advised me, at this time, when I attributed the abortion of the flowers to the coldness of our summers, not to raise the temperature of the medium in which my plants were, as I had intended doing, and it will be seen in the sequel that this advice was well founded.
*I see in M. Jongee's letter (4th November) that he found under each stem, and attached to the roots, 6 or 8 tubers. This I think is a mistake. The tubers of Olluco appeared to me exactly like those of Potatoes, and like them to spring exclusively from the lower part of the stem. The figure accompanying M. Decaisne's article in the "Revue Horticole," in consequence of a mistake in the colouring, also seems to make the tubers spring from the root; but that was certainly not the artist's intention.

In general my tubers did not begin to grow till the autumn rains had begun, so that they were still very small when the frosts set in. Some plants, however, under sashes produced tubers in April; but when planted out in May, although great care was taken not to disturb them, they did not continue to increase in size; they behaved like sets, shrinking and sending out new shoots. During the three summer months, vegetation was decidedly checked.; this is to be attributed rather to heat+ than to want of moisture, for those plants which were at this time well watered, produced plenty of leaves but no tubers. The return of a lower temperature was remarkable, on the contrary, for the rapid development of adventitious buds on the tubers;* and this effect was, I think, much more quickly perceptible on those plants which had suffered from drought than on the more vigorous ones which had been watered.

A little later in the season, and when the external atmosphere was damp, the stems presented another  rather curious phenomenon; their extremities which, a few days before, had very short internodes, and leaves in whorls, suddenly lengthened; and becoming more slender, were at last transformed into a thread, bearing at long intervals small, nearly scale-shaped leaves; these threads, after running along the ground or over the neighbouring branches, with a manifest preference for dark places, entered the earth, where their extremities became tubers. They are, I am certain, direct prolongations of the stems, and not, so far as I could discover, axillary productions from the leaves at their extremities. This lengthening of the stem into a thread appears to me to be connected with moisture and a low temperature. It took place, in those plants which I had put in a cold pit, in the spring; but being less general it had not struck me so forcibly as it did in the autumn, when it took place on all the plants. In the spring plants, the first threads which were developed entered the earth and formed tubers, whilst those which appeared later, or which met any obstacle, again, under the influence of a higher temperature, gave birth to leaves regularly arranged; the internodes shortened, the stem assumed its natural size, and at the same time sought the light. I thus witnessed the curious phenomenon of stems undergoing two successive contractions and thickenings. This is certainly very interesting, and well deserves the attention of physiologists; for there is a great difference between the weakness produced by lowering the temperature and accompanied (in those parts, too, which still preserved their green colour) with a preference for darkness and that caused by the absence of light and joined (in the same parts, but then nearly always not green) with a powerful tendency to reach the light, as is seen in the shoots emitted by the tubers of the Potato and the Melloco.

+The largest of these tubers were hollow in the inside, but this did not appear to be owing to any decay.

We are not as yet, from any experiments of our own, able to judge of the nutritive qualities of the Melloco. The tubers that came from Peru were not very pleasant to the taste; they, were flabby, semi-transparent, and evidently worn out by the numerous shoots that had grown during the voyage.+ Some Potatoes which were sent along with the Melloco were so altered that it was clearly impossible to come to any conclusion from such samples.

As to the young tubers collected in 1848, the small specimens which I examined were too young to give anything more than a very imperfect idea of the value the plant is likely to acquire as an article of food. Their taste was tolerably pleasant; but (in consequence probably of their not being ripe) they were very watery. With the aid of a microscope I found that there was an abundance of starch in the cortical or outer zones of the young tubers, but less (and that finer) in their interior or medullary portion; the thickness of these two zones, measured from the circumference to the centre, is pretty nearly equal. The grains of starch are roundish, very smooth, rather large, and net unlike those of Oxalis crenata or Oca.

M. Masson, gardener of the Horticultural Society, recommends the leaves of the Melloco in the form of Spinach. I must say that, for my own part. I did not like it; but I ought to add, perhaps, that Basella, and in general all those plants which become viscid when cooked, are not to my taste. M. Masson succeeded much better than I in cultivating the Melloco; his plants were in summer not so strong and vigorous as my own, but when, on the first approach of frost, which was towards the end of October, 1 pulled my plants up, he covered his over with dry leaves, under which the tubers went on growing capitally; he showed me several weighing from 50 to 60 grammes. Not withstanding this, the Melloco did not appear to me to be likely to become of much value in an agricultural point of view, at least with us; but I think it is worth keeping in our kitchen gardens, even if it is not at present of any great importance. The time may come when, in consequence of some change in temperature, different from that of this year, the fruit may ripen; in which case there will be a chance at least of raising plants from seed, which may be more valuable than the original ones; and even without that, experience may teach us how to bring about the first development of the tubers soon enough to enable them to attain a considerable size, and to ripen completely before the frosts set in.

From my own observations, a short account of which I have just given, I am inclined to think that the climate of England, or still better that of Ireland, would be mere suitable for the Melloco than that of France; and that it is advisable to attempt to introduce the plant into your country. This attempt would be the more likely to succeed when the wonderful facility with which the plant in question is propagated is remembered; in illustration of this I may give you the following remarkable example. Having observed that some flowering branches, which I had destined for my herbarium, had produced under the press several small tubers, I gathered together the stems of some plants which I had pulled up 10 days or so before, and which had been lying on the ground ever since, and put them into a box between layers of dry straw. On opening the box at the end of a fortnight, I found the stems partly rotten, and that they had given birth to 500 or 600 small tubers, varying in size from a Pea to a Hazel nut; some of the stems had as many as 25 tubers distributed over their surface. From the green stems cuttings can be taken, which will strike at any season of the year in the open air. M. Masson considers cuttings formed by a shoot placed in the ground, and merely covered with a handful or two of earth, as the best mode that could be devised of multiplying this plant. I have every reason to believe that the Papalissa mentioned in Dr. Jameson's article is not the same thing as the Melloco or Olluco. I have in my hand five small tubers which I believe belong to the former species, and which were sent to our central agricultural society by M. Victor Paquet. They are very smooth, of a rosy colour, and with eyes rather sunk and differing entirely from those of the Melloco. They apparently belong to a Solanum. The number of tuberous plants afforded by the Corderillas of the Andes is rather curious, for besides the plant in question, there is found there, in a cultivated state (according to M. Boussingault), various other plants used for food, including the Maca, several varieties of Oca, and more whose names I have forgotten. Louis Vilmorin, Paris, Dec. 7.