Background – The still highly incomplete floristic knowledge of ultramafic outcrops in Borneo has been emphasised. Specialised investigation often turns in novel discoveries and in Kinabalu Park, Malaysian Borneo, the recent completion of a floristic inventory has facilitated such research. Methods – Normal practices of herbarium taxonomy have been applied (using material from K, L, MSC, SING and the Kinabalu Park Herbarium). Results – Eriobotrya balgooyi (Rosaceae) is a new species described from Sabah, Malaysian Borneo. It is an obligate endemic to ultramafic soils on a hill near the eastern ridge of Mount Kinabalu and on nearby Mount Tambuyukon, both localities within Kinabalu Park, a World Heritage Site. The new species illustrates a growing list of rarities from the little-documented flora of ultramafic soils that form significant outcrops in northern Borneo, and for which urgent study is needed.

EXTREME ENVIRONMENTS; LOQUAT; MOUNT KINABALU; MOUNT TAMBUYUKON; NARROW ENDEMICS; PERIDOTITE; RARE SPECIES; SABAH; SOUTHEAST ASIA; TAXONOMY; WORLD HERITAGE SITE