Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 96. (Budapest 2004)

Kováts, D.: Some differences in morphological structure of the vegetative parts (herbage) of Sesleria heufleriana Schur and Sesleria hungarica Ujhelyi (Poaceae)

SUMMARY Besides the differences in measurement, a few less marked differences have also been found in the morphology of the two Sesleria taxa (S. heufleriana SCHUR and S. hungarica ÚJHELYI). Observation and measurement show that there is difference in the number of the internodes of the culms, first of all apparent in specimens grown under similar circumstances in an experimental garden, where the culms have had only 1 and (mostly) 2 internodes at Sesleria heufleriana, whereas at S. hungarica the culms have had mostly 3, but occasionally 4 or 5 internodes. Consequently there is not even overlaping in the number of internodes between the two taxa. In the case of the specimens that grew in their original habitats there is complete agreement in the percentage of the number of the culms with 2 and 3 internodes between the two taxa. Difference is manifest between them at 9 per cent: to that tune the specimens of Sesleria heufleriana have no nodes as opposed to S. hungarica in whose case culms with 4 internodes can be found to that amount. Sesleria hungarica is a more robust and taller plant than Sesleria heufleriana, as regards both the culm and its internodes, sometimes double in length. Compared with the average height of the specimens that grew in their original habitats, this difference in measurment is 10 to 15 cm, and in proportional to the height (length) of the uppermost internodes. Contrary to the average data, the length rates of the leaf sheaths and leaf blades change at different levels of the culm in the case of the two taxa. At Sesleria heufleriana the blades of the youngest leaves second from above are already longer than the leaf sheaths, whereas at Sesleria hungarica it takes place only in the case of the youngest leaves third from above. Though the average data have been taken into consideration, no marked difference has been found in the length of the last culm leaf (DEYL 1946: 8), nor in the length of the leaf blades, nor in that of the leaf sheaths. Through the above observations, measurements, and their comparison, author has intended to contribute to the separation of the two Sesleria taxa. Acknowledgements - I gratefully acknowledge my indebtedness to my sons DEZSŐ KRISTÓF KOVÁTS and SZABOLCS MIKLÓS KOVÁTS, who rendered me invaluable help with computer editing, especilly with the tables and graphs.