Stachys boluensis (Lamiaceae), a new species from northern Anatolia, Türkiye, with neotypification of S. thirkei

Türkiye represents one of the principal centres of diversity for the genus Stachys, exhibiting a remarkably high level of endemism, with 70 of the 126 (98 species) currently recognized taxa (55.5%) being endemic to the country. In this study, we describe and illustrate Stachys boluensis (Lamiaceae), a new species of sect. Eriostomum endemic to Bolu Province, Türkiye. Morphologically, the new species is closely related to S. thirkei but differs in having shortly adpressed-villous or densely adpressed arachnoid-tomentose flowering stems with subsessile glandular hairs, a calyx 12–17 mm long with ovate-lanceolate teeth 5–7 mm long, a white corolla, and pale-brown, broadly obovoid to subglobose nutlets with a reticulate-smooth surface. In addition, a neotype is designated here for S. thirkei to ensure nomenclatural stability.