Acer pentapomicum J.L.Stewart

Native to the northwestern Himalayas, Acer pentapomicum occurs in the upper reaches of the basins of the five rivers of the Punjab, for which the region is named (Punjab translates from Persian as “Land of Five Waters”). This would most accurately be Latinised as pentapotamicum, translating as “of the five rivers”, but unfortunately it was mis-spelt by Stewart when formally describing the species (van Gelderen, de Jong & Oterdoom 1994; Clarke 1988, van Gelderen & van Gelderen 1999). Though Bean (1976a) included the species under this name (Acer pentapotamicum) on assumption that this was Stewart’s intention, later authors acknowledged that such reasoning does not constitute legitimate reasoning for such a change and reverted back to the original spelling (van Gelderen, de Jong & Oterdoom 1994; Clarke 1988).

The species was speculated to be absent from gardens by Bean (1976a), with plants grown as this at Kew and Borde Hill at that time proving to belong to A. acuminatum. Plants so-named in Irish collections were also evidently mis-identified (Bean 1976a). van Gelderen & van Gelderen (1999, p. 207) described it as “not a great beauty”, the species being “a collector’s item and is very rare in cultivation”. An accurate assertion, it evidently remains very scarce in collections and certainly falls into the “botanical interest only” category. Two plants were added to the Westonbirt collection in 2024 from garden origin seed received from Gareev Botanical Garden, Kyrgyzstan as A. regelii and have so far made little more than a metre (pers. obs). The species is also represented at The Morton Arboretum, including a plant of wild origin donated by the Vácrátót Botanical Garden, Hungary, grown from material collected from the Hissar Mountains in Tajikistan (Morton Arboretum 1985 onwards).