I was saddened and quite shocked when I received the phone called informing me that Professor Zhengyi Wu had died.It was the evening of June 20th,2013.I had just got off a plane from Tibet and tumed on my mobile phone.Prof.Wu had been unwell for nearly a year.I knew that this would happen one day,but refused to believe it would really come to pass.A few days ago,some students and I were on a field trip in Tibet.Sitting in our jeep,I watched the mountains and roadside as we drove,and tried to identify the plants along the route.The mountain roads in Tibet seem to always make my students sleepy.I woke them up.I told them that I had heard this first when Prof.Wu was on a field trip to Tibet.During the trip,he always kept an eye on the surroundings outside the vehicle,observing plants and taking notes.At the end of each day,he would prepare a check-list of plants for the region through which he had travelled.Back home it was the middle of the night,and I was awake.My thoughts had tued to my relationship with Professor Wu (Fig.1).