Morphological, Palynological and Micromorphological Investigations on Unusual Tanacetum nivale Sch.Bip. (Asteraceae)

The genus Tanacetum L., is one of the cosmopolitan members of the tribe Anthemideae (Asteraceae), encompassing approximately 160 species. Within Türkiye, 61 taxa are recorded, 27 of which are endemic. This research investigates Tanacetum nivale Sch.Bip. using LM and SEM to assess its morphological, pollen, and achene traits, providing additional characters that may assist in resolving systematic issues within the genus. An expanded and revised description is presented based on specimens collected in the Cilo Mountains in Hakkari. The pollen exhibit isopolar, radial symmetry, and a trizonocolporate aperture type. They display an oblate-spheroidal shape, with a polar axis measuring 25–30 μm and an equatorial axis measuring 26–32 μm. The exine ornamentation is echinate with a microreticulate-rugulate pattern observed between the spines. The achenes are straw-colored, obconical-oblong, 1.24–2.15 × 0.32–0.62 mm, with scalariform-verrucate-striate surface ornamentation. The obtained data will shed light on future studies on other taxa of the genus Tanacetum, and contribute to systematic characters for the discrimination of taxa based on morphological, palynological, and achene macro-micromorphological features.