Acer griseum and other compound -leaved Acers with dark imbricate scales on their buds

There is an Acer griseum beside the driveway into Hadlow College - and it is very nearly the recorded size of the County Champion at Cherry Ingram's old house, the Grange at Benenden.

The vegetative Acer key moves into Group B, when you are looking at trees with compound leaves, and then into either trifoliate or pinnate leaves. The next important step is to look closely at the buds. If there are just two non-overlapping bud scales, then you are off towards cissifolium, henryi, and negundo. A. cissifolium has brown woody second year twigs, and trifoliate leaves with pointy leaflets, while the other two have green or purplish second year twigs. A. henryi has trifoliate leaves while A, negundo is the familiar Box Elder with pinnate leaves, normally five. I can deal with these in a separate post focussing on Acer negundo.

If there are more than four dark overlapping scales, then you are off towards mandschuricum, triflorum, griseum and maximowisczianum (nikkoense). A. mandschuricum, The Manchurian Maple, a smallish upright tree with good autumn colour, has glabrous (contrasting red) petioles with quite lanceolate slightly toothed leaflets, while the petioles of the other three are hairy-fuzzy. A. triflorum has the underside leaf pubescence largely restricted to the main veins, and the bark coarsely vertically fissured. A. griseum and maximowisczianum (nikkoense) have obvious pubescence under their leaves, with peeling orange bark on A. griseum, and smooth bark on A. mazimowisczianum. The former tends to few lobes decreasing towards the apex, while the latter has perhaps more shallower lobes or blunt teeth of equal size.

A. griseum is the commonest seen as an ornamental tree in the west, as the overall effect is quite stunning, while the other species are quite rarely planted. From a distance the leaves of A griseum are an attractive matt almost grey-green against the orange curls of the trunk and branches.