Understanding the plant diversity on the roof of the world—A brief review of Flora of Pan-Himalaya

Pan-Himalaya covers the northeastern Hindu-Kush, Karakoram, Himalaya, and Hengduan mountains. These majestic mountain ranges form the highest region in the world, which is called ‘the roof of the world'. Of the 35 recognized biodiversity hotspots in the world, three are wholly or partially included in Pan-Himalaya, i.e., Himalaya, Mountains of Southwest China, and Indo-Burma. However, although this region is an important and indispensable source of biodiversity, the plant diversity of Pan-Himalaya is poorly known. There is even no complete record of the flora for this most unique region. Currently, climate change and loss of global biodiversity are huge risks facing human society. Understanding the components and changes of plant diversity on the roof of the world will definitely provide new insight into these ecological crises.