POTATO. Solanum tuberosum, Linn. Solanacece, (Irish, English, Round, White Potato.) Figs 741-762.
A farm crop grown for its tubers, which are used largely for human food and for stock-food, and for the manufacture of starch and alcohol, The genus Solanum comprises perhaps 1000 spe cies, in many parts of the world. Some twenty of the described species are more or less tuber-bear ing, but J. G. Baker (Journal Linnieus Society, XX) considers that only six of these "possess a fait claim to be considered as distinct species in a broad sense." These six are Solanum tuberosum, S. 3.1aglia, S. Cornmersoni, S. eardiophyllum, S. James ii, S. oxy earyunt. Of these, only S. tuberosum is known agri cuturally. It is possible, however, that S. Alaglia (the Darwin potato) and S. Comtnersoni (Fig. 103) possess value for the cultivator, either directly or hybridized with the common potato. S. Cornmer soni is now receiving considerable attention in Europe. It is native in Uruguay and Argentina "in rocky and arid situations at a low level." S. Malta is native in the coast regions of Chile, while S. tuberosum occurs natively in the hill country of the interior of Chile and Peru. Forms of S. tuberosum occur in Mexico, and one of them (var. boreale) is native as far north as southern Colorado.
The potato is perennial by means of its tubers. Its smooth, generally solid, more or less quadrangular stems attain a height of two to five or more feet. The stems bear com pound leaves of oval leaflets and small intermedi ate leaflets. The flowers are in clusters and have a five-pointed, wheel-shaped corolla, one to one and a half inches in diameter and varying in color from white to purple. (Fig. 741.) Stamens 5 ; pistil 1, 2-celled. The tine fibrous roots penetrate the soil to the depth of two to four feet, and frequently ex tend horizontally two feet distant from the stems. The fruits or seed-balls are globular, three-fourths to one and one-half inches in diameter, and green, yellowish or purple in color. (Fig. 762.) The tuber is an underground stem ; it bears buds, and, when planted, tends to produce plants similar to its parent; hence tubers are used for perpetuating a variety, and such are generally designated "seed tubers" or "seed."
Varieties vary considerably in composition ; an average of many analyses is: Water, 75 per cent; protein, 2.5 per cent; ether extract, .08 per cent; starch, 19.87 per cent ; fiber, .33 per cent ; other non-nitrogenous materials, .77 per cent ; ash, 1 per cent ; undetermined, :15 per cent ; 85 to 95 per cent of the total dry matter is digestible.
History.
The potato was thought by De Candolle to have been in cultivation in Peru for probably 2,000 years. G. de la Vega found the Peruvians cul tivating it in 1542. He sent tubers to Europe. Various importations were made by the Spanish, and the potato became known in parts of Europe before it was introduced into Ireland in 1586 by Thomas Herriot, who was a member of the expe dition sent to America by Sir Walter Raleigh. The Virginian colonists probably secured potatoes from the Spanish, and they soon proved a valuable acquisition.
It is a common opinion that the aborigines of Virginia cultivated the potato at the time of the discovery. W. R. Gerard asserts, however ("Scien tific American," September 15, 1906), that the °penal& of Thomas Herriot (a product much quoted or discussed in the later writings on the potato), supposed to have been the potato, is really the ground-nut, Apios tubcrosa. He contends that the potato was secured by Raleigh's expedition, under his cousin Sir Richard Grenville, on the return voyage, from a Spanish ship hailing from St. Domingo and cap tured in mid-ocean. The potato was cultivated in Ireland long before it was known in England. Probably the potato was served as an exotic rarity at a Harvard installation dinner in 1707 ; but the tuber was not brought into cultivation in New England till the arrival of the Presbyterian immigrants from Ire land in 1718. The potato of Shake speare was what we now know as the sweet-potato, which derived its name from the aboriginal word botata or batata ; this word or its derivative was later applied to our common or Irish potato. The abo riginal word is still preserved to us in the Latin name of the sweet potato, .1poinaa (or Convo/vulus) Batatas.