L. Hably szerk.: Studia Botanica Hungarica 19. 1986 (Budapest, 1986)
Hably, Lilla: Analysis of leaf size of the Ipolytarnóc flora from a climatological point of view
STUDÏA BOTANICA HUNGARICA (Antea: Fragmenta Botanica) XIX. 1986 p. 23-52 Analysis of leaf size of the Ipolytarnóc flora from a climatological point of view By L. HABLY (Received November 30, 1985) Abstract: Leaf-size analyses have been carried out on a Lower Miocene sample of about 1220 individuals from Ipolytarnóc, the first study of its kind in Hungary. A subtropical moist climate is suggested by the relationship between climate and leaf-size. This conclusion is in accordance with earlier findings based on species composition. The Ottnangian (Lower Miocene) flora from Ipolytarnóc has so far yielded about five thousand specimens (HABLY 1985), including series of several hundred specimens for various species, rendering a statistical analysis of the material possible. MATERIAL AND METHOD Species preserved as impressions of measurable size, i.e. more or less complete, have been studied. Usually there was no difficulty in measuring the length and width of the lamellae as they have mainly been excellently preserved in riolite tuff. In a few cases, especially for Quercus crucita , the length measurements could not be taken with certainty so they have been omitted from the analyses. This study is based on the well-known relationship between leaf-size and the character of the climate (WEBB, 1959, DOLPH & DILCHER 1979, DOLPH & DILCHER 1980 a, b). The above studies were based on actual field studies and large sampie sizes. Their results suggest that this method is suitable for drawing palaeo-climatologica! conclusions, although it is a rather difficult exercise as recent study material is not available in sufficient numbers. Therefore in palaeobotany mainly relative comparisons are made, i.e. leaf-size categories calculated in the same way are compared between various localities. WEBB (1959) used three leaf-size categories: microphyll < 7.6 cm, notophyll 7.6 - 12.7 cm (20.25 - 45.0 sq cm), mesophyll > 12.7 cm (45.0 - 182.25 sq cm). Referring the leaves to either of these three leaf categories, WEBB gave percentile frequency in each of the climatic forest associations, as follows: Tropical Rain-forest region: MVF, SEVF, DVT (lowland and lower montane), SMVF, NVF, SNVF, AVW (lower montane or montane), MMT (montane). Subtropical Rain-forest region: NVF, AVF, AVW, SEVT (lowland and lower montane), AVF, SNVF (lowland and lower montane), MMF, MMT (montane). Temperate Rain-forest region: SNVF, MMF (lowland and lower montane), MMF, MMT (montane). The percentile frequency of the mesophyll and microphyll leaves, as well as those of the species and specimens are given for each of the above forest types. This is one of the aspects that may be compared with the results of this study, that is, the percentile frequency distribution of leafsizes, in order to determine which climatic forest type the Ipolytarnóc flora belonged to. 2:i
