Taxonomic relevance of stem and leaf anatomy in 10 endemic Fritillaria species from the Mediterranean Region

Fritillaria has important medicinal and horticultural values. This research aims to comprehensively assess the taxonomic relevance of micro-anatomical features within ten species belonging to Fritillaria subgenus Fritillaria, namely F. aurea, F. bithynica, F. crassifolia, F. enginiana, F. glaucoviridis, F. kittaniae, F. serpenticola, F. sibthorpiana, F. wendelboi, and F. whittallii, utilizing light microscopy. The majority of these species exhibit endemism within the Turkish Mediterranean Region, with F. aurea and F. crassifolia representing endemic Irano-Turanian elements, while the rest are native to the Eastern Mediterranean Region. In this anatomical investigation, we described and compare the cross-sections of the stem and leaves. Results revealed substantial variation in anatomical traits among the studied species. The presence or absence of eglandular trichomes, crystal granules in the leaf surface and cross section and in stem pith region, and the arrangement of parenchymal and sclerenchymal layers in the stem offered useful taxonomic markers. Similarly, leaf characteristics such as epidermal cell sizes, stomatal indices, mesophyll types, and guard cell shapes provided distinguishing features. A dichotomous key was developed based on these anatomical traits to aid in the accurate identification of Fritillaria species, highlighting the practical utility of these features in taxonomic studies. The findings underscore the importance of micro-anatomical traits as valuable tools for distinguishing and classifying plant species, especially in cases where morphological traits alone may not provide sufficient differentiation.