In no country has the species been found wild with such certainty as in Abyssinia, Sennaar, and the Kordofan. The expressions of authors and collectors are distinct on this head. The castor-oil plant is common in rocky places in the valley of Chiré, near Goumalo, says Quartin Dillon; it is wild in those parts of Upper Sennaar which are flooded during the rains, says Hartmann.[2116] I have a specimen from Kotschy, No. 243, gathered on the northern slope of Mount Kohn, in the Kordofan. The indications of travellers in Mozambique and on the coast of Guinea are not so clear, but it is possible that the natural area of the species covers a great part of tropical Africa. As it is a useful species, and one very conspicuous and easily propagated, the negroes must have early diffused it. However, as we draw near the Mediterranean, it is no longer said to be indigenous. In Egypt, Schweinfurth and Ascherson[2117] say the species is only cultivated and naturalized. Probably in Algeria, Sardinia, and Morocco, and even in the Canaries, where it is principally found in the sand on the sea-shore, it has been naturalized for centuries. I believe this to be the case with specimens brought from Djedda, in Arabia, by Schimper, which were gathered near a cistern. Yet Forskal[2118] gathered the caster-oil plant in the mountains of Arabia Felix, which may signify a wild station. Boissier[2119] indicates it in Beluchistan and the south of Persia, but as “subspontaneous,” as in Syria, Anatolia, and Greece.
Rheede[2120] speaks of the plant as cultivated in Malabar and growing in the sand, but modern Anglo-Indian authors do not allow that it is wild. Some make no mention of the species. A few speak of the facility with which the species becomes naturalized from cultivation. Loureiro had seen it in Cochin-China and in China “cultivated and uncultivated,” which perhaps means escaped from cultivation. Lastly, for the Sunda Islands, Rumphius[2121] is as usual one of the most interesting authorities. The castor-oil plant, he says, grows especially in Java, where it forms immense fields and produces a great quantity of oil. At Amboyna, it is planted here and there, near dwellings and in fields, rather for medicinal purposes. The wild species grows in deserted gardens (in desertis hortis); it is doubtless sprung from the cultivated plant (sine dubio degeneratio domestica). In Japan the castor-oil plant grows among shrubs and on the slopes of Mount Wuntzen, but Franchet and Savatier add,[2122] “probably introduced.” Lastly, Dr. Bretschneider mentions the species in his work of 1870, p. 20; but what he says here, and in a letter of 1881, does not argue an ancient cultivation in China.
The species is cultivated in tropical America. It becomes easily naturalized in clearings, on rubbish-heaps, etc.; but no botanist has found it in the conditions of a really indigenous plant. Its introduction must have taken place soon after the discovery of America, for a common name, lamourou, exists in the West India Islands; and Piso gives another in Brazil, nhambuguacu, figuero inferno in Portuguese. I have received the largest number of specimens from Bahia; none are accompanied by the assertion that it is really indigenous.
In Egypt and Western Asia the culture of the species dates from so remote an epoch that it has given rise to mistakes as to its origin. The ancient Egyptians practised it extensively, according to Herodotus, Pliny, Diodorus, etc. There can be no mistake as to the species, as its seeds have been found in the tombs.[2123] The Egyptian name was kiki. Theophrastus and Dioscorides mention it, and it is retained in modern Greek,[2124] while the Arabs have a totally different name, kerua, kerroa, charua.[2125]
Roxburgh and Piddington quote a Sanskrit name, eranda, erunda, which has left descendants in the modern languages of India. Botanists do not say from what epoch of Sanskrit this name dates; as the species belongs to hot climates, the Aryans cannot have known it before their arrival in India, that is at a less ancient epoch than the Egyptian monuments.
The extreme rapidity of the growth of the castor-oil plant has suggested different names in Asiatic language, and that of Wunderbaum in German. The same circumstance, and the analogy with the Egyptian name kiki, have caused it to be supposed that the kikajon of the Old Testament,[2126] the growth, it is said, of a single night, was this plant.
I pass a number of common names more or less absurd, as palma Christi, girasole, in some parts of Italy, etc., but it is worth while to note the origin of the name castor oil, as a proof of the English habit of accepting names without examination, and sometimes of distorting them. It appears that in the last century this plant was largely cultivated in Jamaica, where it was once called agno casto by the Portuguese and the Spaniards, being confounded with Vitex agnus castus, a totally different plant. From casto the English planters and London traders made castor.[2127]
Walnut—Juglans regia, Linnæus.
Some years ago the walnut tree was known to be wild in Armenia, in the district to the south of the Caucasus and of the Caspian Sea, in the mountains of the north and north-east of India, and in Burmah.[2128] C. Koch[2129] denied that it was indigenous in Armenia and to the south of the Caucasus, but this has been proved by several travellers. It has since been discovered wild in Japan,[2130] which renders it probable that the species exists also in the north of China, as Loureiro and Bunge said,[2131] but without particularizing its wild character. Heldreich[2132] has recently placed it beyond a doubt that the walnut is abundant in a wild state in the mountains of Greece, which agrees with passages in Theophrastus[2133] which had been overlooked. Lastly, Heuffel saw it, also wild, in the mountains of Banat.[2134] Its modern natural area extends, then, from eastern temperate Europe to Japan. It once existed in Europe further to the west, for leaves of the walnut have been found in the quaternary tufa in Provence.[2135] Many species of Juglans existed in our hemisphere in the tertiary and quaternary epochs; there are now ten, at most, distributed throughout North America and temperate Asia.
The use of the walnut and the planting of the tree may have begun in several of the countries where the species was found, and cultivation extended gradually and slightly its artificial area. The walnut is not one of those trees which sows itself and is easily naturalized. The nature of its fruit is perhaps against this; and, moreover, it needs a climate where the frosts are not severe and the heat moderate. It scarcely passes the northern limit of the vine, and does not extend nearly so far south.