and most others seen by Westerners in southeast China probably originated at the celebrated Fa Ti gardens near Canton. By the first half of the 19th century, according to various Western accounts, air layering was the primary propagation method for penjing, which were then generally between one and two feet in height after two to twenty years of work. Elms were the main specimens used, along with pines, junipers, cypresses, and bamboos; plums were the favored fruit trees, along with peaches and oranges. The branches could be bent and shaped using various forms of bamboo scaffolding, twisted lead strips, and iron or brass wire to hold them in place; they could also be cut, burnt, or grafted. The bark was sometimes lacerated at places or smeared with sugary substance to induce termites ("white ants") to roughen it or even to eat the similarly sweetened heartwood. Rocks with moss or lichens were also a frequent feature of these compositions. The earliest known photograph from China which included penjing was made c.1868 by John Thomson. He was particularly delighted by the collection in the garden of the Hoi Tong Monastery on Henan Island near Guangzhou. A collection of dwarf trees and plants from China was also exhibited that year in Brooklyn, New York. In America, laws such as the Chinese Exclusion Act led to Japanese bonsai becoming more familiar to Americans. This led to the prevalence of knowledge of the Japanese forms of dwarf potted trees for the next several decades and prior to Chinese forms. Near the end of the 19th century, the Lingnan or Cantonese school of "Clip and Grow" styling was developed at a monastery in southeast China. Fast-growing tropical trees and shrubs could be more easily and quickly shaped using these techniques. 20th century Established in 1954, the Longhua nursery in Shanghai included the teaching of classical theory and all aspects of the practice of penjing, a process which could take student-gardeners ten years. As late as the early 1960s, it is reported that some 60 characteristic regional forms of penjing could be distinguished by the expert eye. A few of these forms dated back to at least the 16th century. During the upheaval of the Great Proletarian Cultural Revolution (May 1966-April 1969), one relatively small effect was that many collections of penjing in Mainland China, especially around Beijing, were damaged or neglected because they were seen as