I think there can hardly be a doubt that the largest-flowered plant, whose varieties I have included under the Stirps I., is the true cultivated Potato, a species, in its wild state, confined to the west of the Andes. Whether the & Commersonii, which chiefly differs in the size of the flowers, be really distinct or not, is another question. Ranging as as it does from one side of the contineut to the other, it may perhaps have some claims to be considered the type of the Potato, of which the large-flowered variety, now commonly cultivated with us, is confined, as just observed; to the Pacific side of South America.
That both produce tubers, called "Papas" and "Maglia," is evident, for the specimen from which the tubers were reared to the size of ordinary Potatos, in the Horticultural Society's Gardens, is certainly referable to the small-flowered Valparaiso plant, also collected by Bridges ; and the large-flowered species of Lima presents the ordinary varieties of the well-known vegetable, as does the Chouos Arcliipelago and Mendoza one.
To show how little evidence is to be derived from the mere fact of the species producing tuberous roots, I may mention that there is a third plant, allied to both the former, and found over a great part of extra-tropical South America, bearing tubers, altogether similar to those of the two foregoing Solatia. This I refrain from naming, though unable to ascertain that it is previously described, but it may readily be recognized by its great general resemblance to S. Commersonii, from which it differs in the small fruit, and in the short cupuliform or hemispherical calyx, whose lobes are short, broad, and rounded; while in other respects, as regards pubescence and size and form of the leaflets, it is as variable as the two former. I have seen specimens from Antueo {Reynolds), Valdivia {Bridges, 719), Valparaiso {Cuming, 555), and Uraguay {Tweedie), to the last of which the collector has added ou the ticket, "This bears a considerable quantity of nasty soft watery Potatos at its root, called Papas Amargas, in consequence of their bitter taste."
With regard to Mr. Darwin's specimens, in producing an abundance of tubers they only follow the habit of Cardamine liirsuta and many other plants, when inhabiting such a soil as a shingly beach. In the absence of a bitter principle, evident in the wild tubers of the "Maglia" of the drier parts of South America, the Chonos Archipelago Potato may be compared with the Celery meutioned at p. 287, whose insipidity I attribute partly to the dampness of the climate, and still more to the absence of the direct rays of the sun.
Professor Henslow, who has investigated the subject of the native Potato with his usual care and skill, agrees with me in considering this of Mr. Darwin's to be quite identical with the common cultivated Potato ; and he further remarks the differences between it and the "Maglia" of Chili, without, however, pronouncing them specifically distinct.
Thus, from the information I have been able to obtain, it appears very possible that the plant experimented upon in the Horticultural Society's Gardens, is even specifically distinct from the common cultivated Potato, for it is certainly the small-flowered "Maglia" of Chili, and not the large-blossomed "Aquinas" of Chiloe and the Chonos Archipelago. It woidd be very interesting to introduce the tubers of Mr. Darwin's S. tuberosum, and the S. Commersonii (the latter both from the east and west coasts), into our gardens ; along with, if possible.the short-calyxed species, winch is also stated by Mr. Tweedie to produce tubers.
Though I have spoken of these three Solana as all tuberous-rooted, it is more than probable that they are not always or necessarily so, and that the absence of those hybernacula does not indicate specific distinction. Mr. Cruikshanks, who has studied one of the above species in its cidtivated state in Chili (probably the S. Commersonii), says of it, that the "Papas Amarillas," or Yellow Potato of Peru, which was grown in the Horticultural Society's Gardens, is a variety of the Solatium tuberosum, differing from all other known varieties of that species in its partiality for a particular climate. Mr. Cruikshanks also remarks, "that it will not produce bulbs near the coast in Peru, nor at Valparaiso, but only on the higher parts and in a very few spots; but that further south in Chili, as near Valdivia, it is very productive." The explanation seems to be, that this yellow Potato, whether a species or variety, is dependent upon a moist and cool climate for the formation of tubers, or, as the inhabitants of Peru express
