Tree 8–10 m, though usually smaller in cultivation. Branchlets glabrous, fresh green and very vigorous. Leaves deciduous, 20–25 × 7.5–11 cm, palmately three-lobed, divided to half or one-third of the length, upper surface dark green and glabrous, lower surface pale green, margins coarsely lobed to entire, apex acute to acuminate; petiole 2–4 cm long. Inflorescence terminal, corymbose. Flowers 5-merous, cream to yellow. Van Gelderen et al. 1994, van Gelderen & van Gelderen 1999. Distribution INDIA: Sikkim; MYANMAR; THAILAND. Habitat Moist forest. USDA Hardiness Zone 9–10. Conservation status Not evaluated. Illustration Delendick 1978, van Gelderen & van Gelderen 1999; NT75.
This tender tree was introduced from Thailand to Sydney by the Australian botanist and horticulturist Peter Valder, and from there scions reached Firma C. Esveld in Boskoop, from which source material was distributed to other maple enthusiasts in Europe (J. Harris, pers. comm. 2006). The species survived for a decade at Esveld but was eventually killed by frost, and A. calcaratum was feared lost from cultivation (van Gelderen & van Gelderen 1999). Fortunately this is not the case, as it is grown by James Harris at Mallet Court Nursery, in a polytunnel, where it seeds freely and breeds true, enabling it to be made commercially available – and it is also now growing again at Esveld. Young plants are therefore occasional in cultivation, but require a warm, sheltered position to prosper. The evergreen leaves are rather elegant, and borne on green stems.