Early travellers along Tasmania’s rivers often saw what looked like the top of a bunch of celery sticking up above the general rainforest canopy. They called the tree that bears it Celery-top Pine. Botanists took a different view and thinking that the foliage resembled that of a Spleenwort, gave it the specific name aspleniifolius. They put it in the genus Phyllocladus.
So the botanical name of Celery-top Pine is Phyllocladus aspleniifolius. The Greek word for leaf is phyllon and that for branch is cladon. So the name, daunting at first sight, actually tells us that the flattened branchlets (cladodes), which contain chlorophyll, have taken over the function of the leaves and that the cladodes themselves are shaped like the frond of a Spleenwort (see photo page 9). The true leaves are minute deciduous scales, seen along the edges of the cladodes.
Plants can either bear flowers of one sex only, or can have separate male and female flowers. Often in clusters of 3 or 4, the flowers are borne on the cladode edges and the fruit, like that of a yew, is a small nutlet surrounded by a fleshy aril. Scale bracts at the base of the fruit turn pink or red and swell so that they partly enclose the aril, acting as bird attractants.
Phyllocladus used to be found over a large part of S.E. Asia but today there are only four species, one in Australia and New Zealand and three others in Malesia. They are not pines (Australians give that name to all conifers) but are actually in the southern family Podocarpaceae.
Celery-top Pine is a tree with a straight bole and no buttresses. Although it can be up to 30 metres high, specimens of less than 20 metres are quite common. Needing moist acid soil, in the wild it grows in conditions with cold winters and cool or humid summers with an annual rainfall of 1000-3000 millimetres. Seedlings have long narrow true leaves and quite quickly the new foliage is cladodes, not leaves. Like legumes and casuarinas the tree has a mycorrhizal association which enables it to utilize soil nitrogen, so seedlings should be put into a compost containing unsterilized soil and there are obvious implications for cuttings.
Nowadays it is confined to Tasmania, with a dwarfed subspecies alpina in New Zealand. This latter plant has a green ‘leaved’ and a glaucous ‘leaved’ form. Both can be found in British gardens. As pot specimens they enable gardeners with small gardens or alkaline soil to grow this delightful, handsome and desirable tree.
Author : Jeff Irons
Published: Issue 43 (December 2009)