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A deciduous shrub or tree to 15 m in the wild. Bark grey brown, irregularly fissuring with age. Branchlets soon glabrous, olive or light brown at first, later reddish brown. Buds ovoid, acute tipped, with many pairs of imbricate scales, brown, margins ciliate. Leaves chartaceous to coriaceous, pentagonal in outline, base cordate to truncate, (three-) five-lobed, 3–10 × 8–12 cm, lobes to half the length of the blade, ovate, lateral lobes spreading, basal lobes smaller, apex obtuse to acute, margins entire to lobulate to dentate, upper surface mid green, lower surface paler, sometimes glaucous, pubescent often along veins and in vein axils; petiole 2–10 cm long, green or red, broadening towards the base; autumn colours yellow to brown. Inflorescence terminal, corymbose, peduncle and pedicels pubescent at first, pendulous, up to 20-flowered. Flowers yellow, 5-merous, sepals obovate, 0.3–0.5 cm long, petals oblong-ovate, longer than sepals, stamens eight, inserted inside the nectar disc. Samaras to 3 cm long, wings spreading variously; nutlets rounded to ovoid. Flowering March to April, with the leaves, fruiting in September to October. (van Gelderen et al. 1994; le Hardÿ de Beaulieu 2003; Gregory 2007)
Distribution Albania Azerbaijan Bosnia and Herzegovina Bulgaria Georgia Greece Iran Lebanon North Macedonia Montenegro Serbia Syria Turkey Ukraine
Habitat Mixed deciduous and conifer forest, usually on calcareous substrates, between 400 and 2400 m asl.
USDA Hardiness Zone 5-6
RHS Hardiness Rating H5
Conservation status Least concern (LC)
Acer hyrcanum is, on the whole, a complex of rather unexciting Maples from eastern Europe and western Asia that can really only justify their space in specialist collections. It is however a species complex that requires further study. Seven subspecies are recognised by van Gelderen et al. (1994), while a new, closely related species, Acer mazandaranicum, was described from Iran in 2008 (Amini et al. 2008). Like A. undulatum, from southwest Turkey and also attributable to the complex, it is currently absent from collections. The close relationship of this complex to A. opalus and its relatives should be noted.
Examples of the species (sensu lato) can be relatively large, but in many situations it is often rather small and scrubby. All the subspecies prefer a warm site. At least most are in cultivation, and are occasionally offered for sale by specialists such as Plantentuin Esveld, but notable specimens are rare. Impressive examples however, seemingly of the typical subspecies grow at Westonbirt Arboretum, Gloucestershire, and flower prolifically in late March and early April.
A curious observation noted at Hergest Croft is that A. hyrcanum seedlings make a strong root before the cotyledons emerge – apparently an adaptation to drier habitats. The slow-growing tree there is derived from seed collected on Kop Dag in northeastern Turkey, by R.L. Banks in 1982, outside the known range of any of the subspecies, and has not been identified to subspecific level (L. Banks, pers. comm. 2006).
Tree or shrub to 4–12 m tall; leaves 3–10 cm across, margins flat
Shrub to 2–3 m tall; leaves 0.5–1.5 cm across, margins undulate; Greece, western Turkey
Leaves five-lobed, margins coarsely serrate; samaras 3–4 cm long
Leaves three-lobed or with two additional poorly developed basal lobes, margins entire; samaras not over 1 cm long; southern Turkey
Branchlets glabrous, or soon becoming so
Branchlets persistently pubescent; Lebanon, western Turkey
Leaves dark bluish green above
Leaves green above
Leaves tomentose below, lobes abruptly acuminate; Ukraine (Crimea)
Leaves glabrous, lobes acute to rounded; Albania, Bosnia-Herzegovina, Bulgaria, Croatia, Greece, Macedonia, Serbia & Montenegro
Small tree or shrub, to 5–6 m tall; leaves slightly tomentose below, deeply incised; Lebanon, western Syria, southern Turkey
Tree or rarely shrub, to 10–12 m tall; leaves glabrous, shallowly incised; Asia (Lebanon, western Iran, Turkey), Europe (Croatia, Bosnia-Herzegovina, Serbia & Montenegro)