The Floristic Relationships of the Temperate Forest Regions of China and the United States

Abstract

A diagrammatic illustration is used to explain the meridional shift of the constituents of the Chinese deciduous forests from one in Regions I and II with deciduous trees and few evergreen undershrubs to one in Region III with deciduous species forming the canopy and some evergreen undergrowth, and to one in Region IV with deciduous and evergreen trees mixed. Five samples from the temperate forests of Region III, IV, and VIII are selected to explain the altitudinal variation of the Chinese deciduous forests from eastern to western China, with their obvious limit in western Sichuan and the immediately adjacent portion of Yunnan. A list of the paired or closely related species dominant in the forests is provided to demonstrate the affinities of the deciduous forests of China and the United States. The exact nature of the floristic relationship is explained by distributional maps showing (1) disjunction of the species of Clintonia Raf. with centers of distribution in China, Japan, western United States and the eastern United States, (2) bicentric pattern of distribution of Diphylleia Michaux in eastern Asia and eastern United States, (3) bicentric distribution of Kelloggia Torrey ex Bentham & Hooker restricted to China (Yunnan) and the western United States.