Abstract:

To study the habitat characteristics of wild Physochlaina infundibularis, we made field survey and analysis on its phenological characteristics, community characteristics and soil properties in the middle to eastern section on the northern slope of Qinling Mountains. The following results are obtained. (1) P. infundibularis plants are mostly growing in or around woods with canopy closure ranging from 30% to 45%, at the slope ranging from 15° to 25°, soil layer thickness of 10-20 cm, and surface litter thickness of 3-5 cm. (2) P. infundibularis plants are mostly growing in mid-low altitude mountainous areas, forming a flora with Rhus chinensis, Quercus aliena, Cotinus coggygria, Pterocarya stenoptera and other trees; divided by living habits, there are 36 species in 28 genera of 16 families of woody plants, and 35 species in 22 genera of 12 families of herbaceous plants in the habitat of P. infundibularis. (3) The soil suitable for the growth of P. infundibularis is mostly forest brown soil, and the variation coefficient of soil pH is only 1.54%, which is neutral; the nutrients in the soil are mainly the products of the decomposition of plant litter. The wild P. infundibularis plants are distributed discontinuously in Qinling Mountains, and most of them are distributed in strips or sheets along the slope. In the habitat of wild P. infundibularis, the distribution of water and heat is relatively uniform and stable, and the development of trees, shrubs and grasses is relatively complete. Most populations of P. infundibularis are located in protected areas, with well-preserved vegetation and relatively complete habitats, but such wild plants are basically composed of adult plants, with few new seedlings. Maybe, because the seeds produced by sexual reproduction are not effectively disseminated and germinated, the populations are in improper age structure, which are declining. We speculate that the difficulty of natural regeneration of P. infundibularis is the main reason for its endangerment.

Key words: Physochlaina infundibularis, habitat, associated plant, rhizosphere soil, soil physical and chemical properties