Until the evolution of paper, which is dated traditionally in A.D. 105, the majority of Chinese documents were probably written on boards or narrow strips of wood or bamboo; the use of silk was reserved for the preparation of de luxe copies of certain works, either for sacred or for profane purposes. However, it was only quite recently that actual examples of wooden documents from China were first brought to the attention of the scholastic world, as a result of two series of expedit ions to central Asia and northwestern China. First, Sir Aurel Stein's expeditions, at the be ginning of the century, brought back fragments of inscribed wood from the sites of Tun-huang; thi s was subsequently examined and the results published, by Chinese scholars such as Wang Kuo-wei, an European scholars such as Chavannes and Maspero. Secondly, the expeditions led by Sven Hedin s ome thirty years later found similar material in larger quantities, from the more easterly sites of Chü-yen (Edsen-gol). These texts were published by a number of scholars, beginning with L ao Kan,who was working in China in the extremely difficult conditions of the 1940s.1940s.Shortly afterwards, Japanese scholars were able to turn their attention to this material whose content, l ike thatof the strips from Tun-huang, was almost exclusively concerned with the civil and militar y administration of Han imperial officials, between about 100 B.C.and A.D. 100. In the early 1960 s Professor Mori Shikazo led a series of seminar meetings to study the material from Chii-yen, wh ich the present writer was fortunate and privileged to attend. The results of such meetings were published atthe time in a number of Japanese periodicals, and constituted a valuable contribution to the studyof the wooden material from China known to exist at that time.
A review on the floristic phytogeography in arid northwestern China and Central Asia