Intraspecific leaf morphometric diversity in the endangered and narrow endemic Quercus trojana subsp. euboica (Fagaceae): a quantitative dataset from three natural populations in Euboea, Greece.

This dataset contains the first quantitative leaf morphometric measurements for Quercus trojana subsp. euboica (Papaioannou) K.I.Chr. (Fagaceae), a narrow endemic and endangered oak restricted to the ophiolitic (serpentine) substrates of Northern Euboea Island, Greece. The species is listed in the Red Data Book of Rare and Threatened Plants of Greece and its known range was heavily impacted by the catastrophic megafire of August 2021. Leaf material was collected from 31 georeferenced individuals across three natural populations: Kerasia1 (N=14 individuals), Kerasia2 (N=11 individuals), and Prokopi (N=6 individuals). Approximately 10 mature, fully expanded, sun-exposed leaves per individual were sampled, pressed, dried, and scanned. A total of 301 leaves were processed using a custom Python (v3.12.x) image analysis pipeline incorporating OpenCV, scikit-image, NumPy, and Matplotlib libraries. Fourteen size and shape variables were extracted for each leaf: leaf area, perimeter, major and minor axis length, aspect ratio, circularity, solidity, maximum and minimum Feret diameter, convex area, width-to-length ratio, base-to-wide ratio, petiole-to-lamina ratio, and teeth number. This dataset supports the manuscript "Intraspecific leaf morphometric diversity in the endangered and narrow endemic Quercus trojana subsp. euboica (Fagaceae): a quantitative dataset from three natural populations in Euboea, Greece" submitted to Biodiversity Data Journal.