Platanus orientalis.
The Oriental plane tree is one parent (with P. occidentalis) of the London plane tree Platanus x hispanica.
They are large deciduous trees up to 30 m with a single trunk that is mottled where the bark flakes off.
Occasionally the bark does not flake but fissures.
The alternate leaves are on a hairy petiole with a wide base that surrounds the axillary stem bud.
The stipules are leaf-like with a fused sheathing base.
The palmate leaf blades, up to 25 cm across have 5 (3 or 7) lobes with coarse teeth.
The lobes extend more than half way to the midrib and narrow at the base.
In autumn the leaves turn a yellowish-brown before they fall.
Young stems, leaves, stipules, flower stalks, sepals and fruit all have branched hairs.
These dendritic hairs have a central axis with very short to long side branches.
There are a few small unbranched multicellular ones with a gland near the top.
(A number of variants have been described but not officially accepted apart from the ‘Digitata’ cultivar with more
deeply lobed leaves. There is also a cultivar whose leaves turn more red or orange.)
Pendulous ‘inflorescences’ have 3 to 5 (2 to 7) spherical heads or capitula on a zigzag stalk.
Heads on a stalk have either male or female flowers with both types on each tree.
Flowers are very small and inconspicuous with parts typically in 4’s.
Male flowers have 4 tiny hairy sepals and 4 larger petals.
More prominent are the 4 stamens with a short or no filament and an apical appendage on the anthers.
Female flowers have tiny sepals and 4 prominent styles with a hooked end.
The fruiting heads, up to 2.5 cm across have many tightly packed achenes on a central core.
The obconical achenes have long bristles attached at the base.
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The Missouri Botanical Gardens note that P. orientalis “is somewhat variable in characteristics, and is sometimes
difficult to distinguish from London plane. It also may hybridise with London plane thus creating further variation”.
The Atlas of Living Australia lists 400 reported occurrences of Platanus hispanica and P. hispanica var. ‘Acerifolia’
which is 97% of the total number. The remainder were Platanus orientalis.
Although trees seen around Brisbane have different combinations of features they are almost certainly Platanus x hispanica ‘Acerifolia’.
Three are illustrated in the following sections.
J.F.
