中文摘要：

【目的】为了解中国北方野生杜梨的分布现状并对其进行形态多样性评价，【方法】通过实地调查取样，测定了叶片和果实系列形态指标，评价了野生杜梨居群的龄级结构。【结果】野生杜梨在中国北方主要分布在（32．94～39．74）。N，（107．54～119．16）。E，海拔47～1545m内，有4个集中分布地域，分别为子午岭、伏牛山、太行山和蒙山。不同地域间野生杜梨的叶片、果实和居群龄级结构差异较大，叶片形态多样性以河南省境内野生杜梨最高，同时其单果质量显著大于其他地域．而甘肃华池和宁县野生杜梨果实的单果质量和横纵径最小。野生杜梨居群主要由胸径为2．5～22．5cm的幼树和立木组成。【结论】综合分析，伏牛山区的野生杜梨居群较之其他居群形态多样性丰富，龄级结构更加多样化；我们建议将资源富集和多样性丰富的华池、舞钢和泗水等地的野生杜梨进行重点保护。

英文摘要：

[Objective]The objective of the study were to elucidate understand the distribution situation of wild Pyrus betulaefolia Bunge and assess morphological diversity of this species in northern China. [Method]We performed field investigation, measured several morphological characteristics of leaf and fruit and estimated the age spectrum of wild P. betulaefolia populations. [Result]The results indicated that P. betulaefolia mainly distributed in the area of 32.94-39.74N, 107.54-119.16 E, with elevation from 47 to 1545 meters in northern China. Ziwu Mountain, Taihang Mountain, Funiu Mountain and Mengshan Mountain were four major distribution areas of P. betulaefolia. The age spectrum of population and mor phology of leaf and fruit changed dramatically among different regions. The highest morphological diversity of leaf occurred in populations of P. betulaefolia located in Henan Province. Meanwhile, single fruit weight of P. betulaefolia from these locations was significantly higher than that from the others. Transverse and ver- tical diameters and single fruit weight of P. betulaefolia in Huachi and Ningxian in Gansu Province were re markably smaller than those from other sites. Trees with diameter at breast height ranged from 2.5 to 22.5 cm were the primary constituents of P. betulaefolia. [Conclusion] Populations of wild P. betulaefolia in Fu niu Mountain sustained higher morphological diversity and more complex structure of age spectrum than those from other regions. It was suggested that populations of P. betulaefolia in Huachi, Wugang and Sishui which showed considerablegenetic diversity should be paid more attention on their protection and usage.