Wu Zhengyi was the leading systematic botanist of China during the second half of the 20th Century. His encyclopedic knowledge of Chinese plants, their medicinal uses, and their distributions was shared through a wide variety of publications and directly with his many friends and colleagues. His leadership in completing the Chinese-language Flora Reipublicae Popularis Sinicae to completion, and in co-chairing its later English-language edition, the Flora of China, were perhaps his most important contributions, but he also published widely on a range of other botanical topics. He was also responsible for the preparation of comprehensive accounts on the plants of Yunnan Province and those of Tibet.

Born of an aristocratic family that moved early in his life to Yanzhou, Wu took up the study of botany at Tsinghua University. In order to complete his studies, he was forced in the face of the Japanese invasion to move with the faculty of Tsinghua University from Tsinghua to Changsha and ultimately to Kunming, where he completed his studies e a member of the first generation of Chinese botanists trained in the country. He was an exceptionally brilliant man who developed rapidly as a child and maintained an outstanding level of scholarship all his life. He understood and dealt with the many changes that occurred in China during his life, adapted to them, and was consistently a good citizen as well as an outstanding scientist.

Following his graduation from Tsinghua, Wu conducted postdoctoral studies at Peking University, moving to the Institute of Botany, Chinese Academy of Sciences, Beijing, in 1950 and returning to Kunming in 1958 to direct the CAS Institute of Botany there. He remained in Kunming until his death there 55 years later, presiding over a period of growth in the Institute of Botany and leading it to become a key center for the study and conservation of Chinese plants. He led the study of the plants of Yunnan Province, the richest area for plants in China, eventually helping in the establishment of 24 nature reserves in the province. He also successfully recommended the formation of the Germplasm Bank for Wild Species at the Kunming Institute; it was established in 2004, a very important mechanism for conserving China's plants that has grown rapidly since.

I first met Wu Lao as a member of the Chinese Botanical Delegation that visited the U.S. in 1979, a part of the resumption of botanical relationships between our countries. The following year, I returned to China myself; I had moved in 1937, just as Wu had done and for similar reasons, having been born in Shanghai but just a baby when I left. He welcomed us at the Institute of Botany in Kunming, a much smaller city at the time, but memorably accompanied us on a botanical trip and ascent of Emeishan, in Sichuan Province. Emeishan, 3099 m tall, is one of the four sacred Buddhist mountains of China, a very well-known locality botanically because of its rich flora. The forests there represent a fine assemblage of survivors of the warm-temperate forest that covered great stretches of the Northern Hemisphere until about 15 million years ago, and survived best in a belt across south-central China. We broke our ascent of about 2500mby staying the night in a monastery along the trail, greatly appreciating and studying the plants that grew along the way.

On this excursion I came to knowWu Lao as the scholarly, intellectually curious, and friendly man that he was. Always read to encourage others, he fostered the field of Chinese botany and left behind a lasting legacy in the state of its development now.

In addition to his codification of China's plant species, Wu is credited with making two recommendations that had a large impact on the preservation of Yunnan's rich array of plant species. The first was a 1956 proposal to establish a series of 24 nature reserves in Yunnan, which have played an important role in preserving some of its exceptionally rich biota during the enormous changes that took place over the subsequent sixty years and are continuing to reduce the chances for survival of the plants he loved so much. He also suggested, in 1999, that a national seed back should be established, and today the Kunming Institute of Botany's Germplasm Bank of Wild Species is the largest and most comprehensive in China.

Yu Te-Tsun, who had been the chairman of the editorial committee for FRPS, passed away in 1986. Along with Wu Zhengyi, he had suggested the idea of preparing a joint revised edition of FRPS in English in 1979. Wu Zhengyi succeeded him as chair of the FRPS committee, in 1987, they informed us that the new project had been approved. Certainly the fact that a Chinese committee with wide representation was already overseeing the production of the parent work FRPS expedited launching and producing the Flora of China cooperatively too. Once the Flora of China(in English)had been approved, a joint committee was set up, with Wu Lao and me as co-chairs, and we took the steps necessary to begin our new project. I worked with him and all the members of the committee until the completion of the project in 2014, Wu Lao having handed over the day-to-day supervision of the editorial efforts to Hong De-yuan in 2001 but continuing to take a keen interest in the project until his death in 2013. He certainly knew that it was in effect completed by the time that he passed away, and I'm sure he found satisfaction in the product, the Flora of China, to which he had contributed to much.

I had the personal pleasure of consulting withWu Lao a number of times during the last 34 years of his productive life, especially during the 1990s, both in Kunming and at joint meetings of the Flora of China Editorial Committee. Always positive, he contributed in many ways to our success, and I came to appreciate him very much both as a friend and as a colleague.