L. Hably szerk.: Studia Botanica Hungarica 19. 1986 (Budapest, 1986)

Csontos, Péter: Phytosociological description of a hilly country stand of Impatiens parviflora DC

S T U D I A BOTANICA HUNG A R I C A (Antea: Fragmenta Botanica) XIX. 1986 p. 115-118 Phytosociological description of a hilly country stand of impatiens parvifiora DC. By P. CSONTOS (Received November 30, 1985) Abstract: A stand of Impatiens parvifiora

, an adventive plant in Europe, was studied at Vadálló-rocks, Pilis Mts., Hungary. The stand is situated mostly at the ecotone of a Querco petraeae-Carpinetum pannonicum and a Mercuriali-Tilietum forest. With the shrinking of the well-developed geophyte aspect (mainly Corydalis cava and goUda) Impatiens becomes dominant and remains so during the whole summer until fall. The main reason for its success in colonization is that the natural vegetation leaves a suitable habitat open and accessible for I. parvifiora in time and space. INTRODUCTION Impatiens parvifiora DC. is well-known as a continuously spreading alien species in Europe (MEUSEL et al. 1978). Its first occurrence was noted in 1891 by HORBAS. Later PRISZTER (1965) investigated it in more details and presented a map of its in distribution in Hungary, together with two other alien species (

I. glandulifera Royle and I. balfourii Hook, f.). The communities where I. parvifiora may be found in Hungary have been published by SOO (1964-1980). These are; in floodplain forests: Salicetum albae-fragilis, Fraxino pannonicae-Plmetum, Carici remotae-Fraxinetum, in oak forests: Quercetum petraeae-cerris pannonicum, Convallario-Quercetum roboris, woody and floodplain weed-communities: Cuscuto-Calystegietum sepium. Considering the speedy expansion of the range of Impatiens parvifiora, the list of associations will probably increase. This work was carried out in the Biosphere Reserve of the Pilis Mts. The aim of the study was to describe the communities where I. parvifiora exists and find the reasons of its accommodation. MATERIALS AND METHODS The object of study was an I. parvifiora stand at Vadálló-rocks in the Pilis mountains, Hungary. It is a large, young (not older than 10 years) stand originated by indirect human activity, probably introduced by hikers. Sampling was carried out according to BRAUN-RLANQUET (19641 using 10 permanent quadrats each 100 sq.m. in size and the field work was carried out in 1984 and 1985 (the estimated cover values are: + - -1%, 1 = 1-5%, 2 = 5-25%, 3 = 25-50%, 4 = 50-75%, 5 •= 75-100%). We compiled the data of the samples in a comprehensive table where the A-D values mean the minimal and maximal cover values of each species and Fr stands for the frequency of the given species in the quadrats (l=-20%, 11-20-40%, ... V=80-100% of the quadrats).