蕃薯及 Ground Nut

Digging one day for fishworms, I discovered the ground-nut (Apios tuberosa) on its string, the potato of the aborigines, a sort of fabulous fruit, which I had begun to doubt if I had ever dug and eaten in childhood, as I had told, and had not dreamed it. I had often since seen its crumpled red velvety blossom supported by the stems of other plants without knowing it to be the same. Cultivation has well-nigh exterminated it. It has a sweetish taste, much like that of a frost-bitten potato, and I found it better boiled than roasted. This tuber seemed like a faint promise of Nature to rear her own children and feed them simply here at some future period. In these days of fatted cattle and waving grain-fields this humble root, which was once the totem of an Indian tribe, is quite forgotten, or known only by its flowering vine; but let wild Nature reign here once more, and the tender and luxurious English grains will probably disappear before a myriad of foes, and without the care of man the crow may carry back even the last seed of corn to the great cornfield of the Indian's God in the southwest, whence he is said to have brought it; but the now almost exterminated ground-nut will perhaps revive and flourish in spite of frosts and wildness, prove itself indigenous, and resume its ancient importance and dignity as the diet of the hunter tribe. Some Indian Ceres or Minerva must have been the inventor and bestower of it; and when the reign of poetry commences here, its leaves and string of nuts may be represented on our works of art.

中國把馬鈴薯稱之為土豆顯然是從英文 ground nut 直譯過來。但是 ground nut 是一種藤蔓植物，土下有長在根上頭的塊莖；因其塊莖形狀像個球而得名。也許曾經用來稱呼馬鈴薯，但現在馬鈴薯都改稱 potato 了。 Ground nut 在美洲是原住民的主食，據說內含的蛋白質是一般食用馬鈴薯的三倍。所以梭羅說，這種塊莖是大自然的允諾，允諾在未來某一段時期，（若是世界有了什麼變化），還是可以用來餵養她自己的孩子。

蕃薯英文 Sweet Potato，中國稱之為地瓜。台灣原本是沒有蕃薯的，它是由中南美洲輾轉傳布到世界各地。雖然不是台灣的原生作物，但是十六世紀末，蕃薯幫助台灣先民度過荒蕪與天災。隨著移民的拓墾，蕃薯在台蔓衍茁壯，清朝時更成為輸往中國的高獲利作物。進入日本殖民時代，日人以科學方法栽植改良，使蕃薯質精量盛。六○年代以降，蕃薯從食糧轉型為家畜飼料，協助台灣以畜產品對外貿易，對之後台灣的經濟飆揚，有著不可磨滅的功蹟。現在蕃薯又成為當紅的健康食品。台灣人稱自己為蕃薯仔；蕃薯早已經成為台灣的 ground nut，也是大自然的允諾。有一天世界溫度升高了2度C，所有的外國人都跑了，它就會再用來餵養台灣的蕃薯仔囝。