Authors: L.
to about 40cm or more in height. Leaves deciduous, pedate, divided into five to ten finger-like pinnate lobes. Pinnules irregularly triangular-oblong, 1.5-2cm long, membranous. Himalaya to Japan and North America, mainly in broad-leaved forest. Very hardy and decorative but on the large side for the rock garden. Very variable in the wild and names given to wild collections are often confused or ambiguous. A.p. forma imbricatum has compact leaves with overlapping pinnules. Best for the rock garden are the various dwarf (under 15cm), more or less glaucous selections most commonly named A.p. var. aleuticum (or 'Aleuticum') which is correctly A.p. var. subpumilum and probably the same as 'Nanum' and 'Dyce's Dwarf. A.p. 'Minus' or 'Minor' is also dwarf but differs somewhat. The smallest form of all has been called A.p. var. subpumilum 'Minimum'. True A.p. var. aleuticum has a more erect habit and pinnules deeply and irregularly cleft. 'Klondike' appears to be an unremarkable selection of this. A.p. 'Asiaticum' is similar to var. aleuticum but is 20-25cm tall and duller green. It has given rise to 'Laciniatum' with deeply lobed pinnules. A.p. 'Japonicum' is similar to 'Asiaticum' but the young foliage is a bright reddish bronzy pink though variable in intensity. Several other larger variants are known.
