Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 69. (Budapest 1977)

Szujkó-Lacza, J. ; Sen, S.: Correlation coefficient study in some character pairs of the Hungarian Gentiana (Gentianaceae)

ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Toraus 69. Budapest 1977. Correlation Coefficient Study in Some Character Pairs of the Hungarian Gentiana (Gcntianaceae) by J. SZCJKÓ-LACZA, Budapest & S. SEN, Hoogly Abstract — Out of 38 character pairs, 20 show positive and the rest negative correlation. The characters No. 4 and 5 in G. cruciata and 23 and 24 in Gentianella ciliata, 23 and 38 and 24 and 36 in G. pneurnonanthe show significant negative or positive correlation at different probability level. The pedicels (Nr. 23) is a taxonomically important character in Gentiana since it appears to be genetically controlled, thus under strong regulation of growth regulator. This organ is wholly absent in G. cruciata and G. asclepiadea. In the other two species where it is present it shows significant correlation with other characters. In our previous communication (J. SZUJKÓ-LACZA & S. SEN 1976) we made a detailed numerical evaluation of morphological characteristics of the Hungarian species of Gentiana (according to Soó 1966) with a view to finding out the similarities and dissimilarities and the degree of variability in morphological features among the species. In the present paper we have attempted to find out the correlation coefficient in different character pairs of each species, separately. We are guided here by the assumption that the characteristics of any individual is controlled by its growth regulating activity and if two features are determined by a common metabolic activity, they are likely to show either some positive or negative correlation. Taxonomists and morphologists have always wanted to know the natural units and their natural relationship for classification. These natural units are the part of any circumscribed determinative system. We suppose that there exits some determinative relationship among the characters of different species to be classified. Numerical taxonomists, on the other hand, ho!d a different idea regarding correlation. SNEATH & SOKAL (1973) pointed out that the determination of correlation between the characters of two different species is not desirable since it gives ambiguous results. CLIFFORD'S (1969) view is, on the other hand, contrary to that of SOKAL and SNEATH. He could find significant correlation among various attributes* and used it in the classification of different genera of Poaceae. He also anticipated that a knowledge of the magnitude of these correlations would be useful for determining the relative importance of each attributes for generating taxonomic groups. We have, however, restricted our study only of finding out the correlation if any, in different character pairs of each species separately. No attempt has been made to find out any correlation among the species. Material and methods All our observations are based on dried specimens of Herbarium Budapest (H B). Forty-three exomorphic characters were selected from each species and studied critically. This process was repeated fifteen times on fifteen different specimens of each species. Of these we have selected 12 pairs of quantitative characters from each species for analysis of correlation coefficient. The correlation coefficient of characters has been determined by following SVÁB (1967). The character numbers have been taken from the polytomic key of our previous paper SZUJKÓ-LACZA und SEN (I.e.) Of these, only character No. 4 (i.e. number of stem) is a numeral while the rest are all measurable characters. Character No. 4 = number of stem. Character No. 5 = height of stem. * The term character has generally been used here to describe CLIFFORD'S attributes and SOKAL and SNEATH'S optional taxonomic unit (OTU).