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

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

A-D Fr. A-D Fr Asarum europaeum + I Veronica hederifolia +-2 III Epilobium montanum +-1 I Viola odorata +-1 III Scrophularia vernalis +-1 I Campanula persicifolia Campanula rapunculoides + + -1 !l Quercetea species and Querco-Fagea Galium schultesii +-1 ; i species characteristic for QuerceSorbus torminalis (a) 1 n tea ( X ) Carex divulsa + i xAcer campestre (a,c) + -2 [V Crataegus oxyacantha (b) Ficaria verna Lapsana communis Mycelis muralis 1 1 Cardaminopsis arenosa Cornus mas fa, b, c) Quercus petraea (a,c) xDigitalis grandi flora Fraxinus ornus (a) x Viol a cyanea xCalamintha clinopodium 4 1-4 1-3 + + - 3 111 III III II II II I Crataegus oxyacantha (b) Ficaria verna Lapsana communis Mycelis muralis + +-1 j Cardaminopsis arenosa Cornus mas fa, b, c) Quercus petraea (a,c) xDigitalis grandi flora Fraxinus ornus (a) x Viol a cyanea xCalamintha clinopodium 4 1-4 1-3 + + - 3 111 III III II II II I Staphylea pinnata (b) Scrophularia nodosa + + ï Cardaminopsis arenosa Cornus mas fa, b, c) Quercus petraea (a,c) xDigitalis grandi flora Fraxinus ornus (a) x Viol a cyanea xCalamintha clinopodium +-1 + 111 III III II II II I Veronica chamaedrys Viola mirabilis + +-1 ! xEuonymus europaeus (b, c) Spiraea media 4-1 + ! I Other species xCrataegus monogyna (b) + I Impatiens parvifiora Anthriscus silvestris (1-) 3-5 +-1 V I Querco-Fagea species Lamium album +-1 I Polygonum dumetorum + V Rubus sp. + I Acer platanoides (a, c) Clematis vitaiba (mainly seedlings) + -1 4-1 IV IV Indifferent species Geranium robertianum + -2 IV Alliaria petiolata +-1 V Geum urbanum + IV Galium aparine +-1 IV Melica uniflora 4-2 IV Urtica dioica +-3 [V Poa nemoralis -3 IV Chelidonium majus + 11 Primula veris + -1 IV Glechoma hederacum + II Dactylis polygama +-] III Stellaria media + I Accidental species (found in the herb layer, in one quadrat and with a value of "+" only). Acerion pseudoplatani : Arabis turrita, Fagetalia: Anemone ranunculoldes, Dryopteris filix-mas, Euphorbia amygdaloides

, P

olypodium vulgare

, Quercetea: Achillea distans

. Euphorbia polychroma. xHyp

ericum hirsutum, Querco-Fagea: Arum maculatum

, Chrysanthemum corymbosum

, Hieracium sabaudum, H. sylvaticum, Sambucus nigra observed out of samples. Other species: Lac tue a serriola, Lamium purpureum

, Linaria genistifolia

, Rosa sp

. SUMMARY Immigration of Impatiens parvifiora DC. was investigated in the Biosphere Reserve of the Pilis Mts. Its stand is situated in the greater part at the ecotone of a Querco petraeae - Carpinetum pannonicum and a Mercuriali-Tilietum forest. Under usual circumstances only the spring geophyte aspect is well-developed giving considerable cover in these forests while the summer aspect is of less importance with cover value below 10% in general. It seems that the Hungarian flora did not have any species of the herb layer which could have filled this place with large abundance. I. parvifiora proved to be a suitable species in time and space, so after introduction, being without any competitor it could colonize the vacant habitats within 'a short time. Acknowledgements - I should like to express my thanks to L. LOKÖS for his assistance in the field.