The observations on the habitat of Cannabis sativa agree perfectly with the data furnished by history and philology. I have treated specially of this subject in a monograph in Prodromus, 1869.[721]
The species has been found wild, beyond a doubt, to the south of the Caspian Sea,[722] in Siberia, near the Irtysch, in the desert of the Kirghiz, beyond Lake Baikal, in Dahuria (government of Irkutsh). Authors mention it also throughout Southern and Central Russia, and to the south of the Caucasus,[723] but its wild nature is here less certain, seeing that these are populous countries, and that the seeds of the hemp are easily diffused from gardens. The antiquity of the cultivation of hemp in China leads me to believe that its area extends further to the east, although this has not yet been proved by botanists.[724] Boissier mentions the species as “almost wild in Persia.” I doubt whether it is indigenous there, since in that case the Greeks and Hebrews would have known of it at an earlier period.
White Mulberry—Morus alba, Linnæus.
The mulberry tree, which is most commonly used in Europe for rearing silkworms, is Morus alba. Its very numerous varieties have been carefully described by Seringe,[725] and more recently by Bureau.[726] That most widely cultivated in India, Morus indica, Linnæus (Morus alba, var. Indica, Bureau), is wild in the Punjab and in Sikkim, according to Brandis, inspector-general of forests in British India.[727] Two other varieties, serrata and cuspidata, are also said to be wild in different provinces of Northern India.[728] The Abbé David found a perfectly wild variety in Mongolia, described under the name of mongolica by Bureau; and Dr. Bretschneider[729] quotes a name yen, from ancient Chinese authors, for the wild mulberry.
It is true he does not say whether this name applies to the white mulberry, pe-sang, of the Chinese plantations.[730] The antiquity of its culture in China,[731] and in Japan, and the number of different varieties grown there, lead us to believe that its original area extended eastward as far as Japan; but the indigenous flora of Southern China is little known, and the most trustworthy authors do not affirm that the plant is indigenous in Japan. Franchet and Savatier[732] say that it is “cultivated from time immemorial, and become wild here and there.” It is worthy of note also that the white mulberry appears to thrive especially in mountainous and temperate countries, whence it may be argued that it was formerly introduced from the north of China into the plains of the south. It is known that birds are fond of the fruit, and bear the seeds to great distances and into uncultivated ground, and this makes it difficult to discover its really original habitat.
This facility of naturalization doubtless explains the presence in successive epochs of the white mulberry in Western Asia and the south of Europe. This must have occurred especially after the monks brought the silkworm to Constantinople under Justinian in the sixth century, and as the culture of silkworms was gradually propagated westwards. However, Targioni has proved that only the black mulberry, M. nigra, was known in Sicily and Italy when the manufacture of silk was introduced into Sicily in 1148, and two centuries later into Tuscany.[733] According to the same author, the introduction of the white mulberry into Tuscany dates at the earliest from the year 1340. In like manner the manufacture of silk may have begun in China, because the silkworm is natural to that country; but it is very probable that the tree grew also in the north of India, where so many travellers have found it wild. In Persia, Armenia, and Asia Minor, I am inclined to believe that it was naturalized at a very early epoch, rather than to share Grisebach’s opinion that it is indigenous in the basin of the Caspian Sea. Boissier does not give it as wild in that region.[734] Buhse[735] found it in Persia, near Erivan and Bashnaruschin, and he adds, “naturalized in abundance in Ghilan and Masenderan.” Ledebour,[736] in his Russian flora, mentions numerous localities round the Caucasus, but he does not specify whether the species is wild or naturalized. In the Crimea, Greece, and Italy, it exists only in a cultivated state.[737] A variety, tatarica, often cultivated in the south of Russia, has become naturalized near the Volga.[738]
If the white mulberry did not originally exist in Persia and in the neighbourhood of the Caspian Sea, it must have penetrated there a long while ago. I may quote in proof of this the name tut, tutti, tuta, which is Persian, Arabic, Turkish, and Tartar. There is a Sanskrit name, tula,[739] which must be connected with the same root as the Persian name; but no Hebrew name is known, which is a confirmation of the theory of a successive extension towards the west of Asia.
I refer those of my readers who may desire more detailed information about the introduction of the mulberry and of silkworms to the able works of Targioni and Ritter, to which I have already referred. Recent discoveries made by various botanists have permitted me to add more precise data than those of Ritter on the question of origin, and if there are some apparent contradictions in our opinions on other points, it is because the famous geographer has considered a number of varieties as so many different species, whereas botanists, after a careful examination, have classed them together.
Black Mulberry—Morus nigra, Linnæus.
This tree is more valued for its fruit than for its leaves, and on that account I should have included it in the list of fruit trees; but its history can hardly be separated from that of the white mulberry. Moreover, its leaves are employed in many countries for the feeding of silkworms, although the silk produced is of inferior quality.