The biodiversity crisis, driven by accelerated habitat conversion, climate change, and other human-induced threats, significantly increases the need for comprehensive taxonomic research aiming for effective conservation strategies. Species conservation initiatives have faced challenges recently, especially in hyperdiverse regions, due to insufficient surveys and misidentification, highlighting the crucial role of taxonomy to address these issues. Lamiaceae, includes about 8,100 species, many with significant economic importance. However, certain lineages within it, such as the South American genus Glechon, remain understudied. Glechon comprises seven species and is primarily distributed in southern Brazil, Argentina, Paraguay, and Uruguay. This study focuses on Glechon hoehneana, a rare and understudied species, endemic to the Brazilian Atlantic Forest. We conducted extensive herbarium and field work and report new localities for G. hoehneana, within the Mantiqueira mountain range, extending the known distribution further north, into Minas Gerais state. A detailed taxonomic description is provided, accompanied by a key to Brazilian species of Glechon, as well as an updated distribution map, and an IUCN conservation status assessment, highlighting its main threats. A clarification on the typification of the genus and its type species is also presented. We call for the increase of botanical inventories and protection of narrow endemic species, particularly in biodiversity-rich but under-protected regions.