Macrozamia douglasii

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Figure 1. M. douglasii in habitat, Fraser Island.

Contents

Introduction:

Fraser Island (off the South Queensland coast) is famous for a number of reasons. It abounds in botanical flora, has magnificent freshwater lakes, is unique in its reptile life (the little dark shelled terrapin of one lake), large belts of rain forest and drier forest are there, heavily wooded wallum country runs through it, and much of the seaward foreshore have really fine coloured sand cliffs. Indeed these latter are possibly better than the coloured sands of Rainbow Beach and Teewah!

Fraser is also noted for its long beaches and is a draw card to recreational surf-cast fishermen from everywhere! Following this pursuit, I spent some days on the island recently and had a chance to examine its cycad which is named Macrozamia douglasii.

Mentioned in several botanical papers, and especially by the late Dr Start Blake of the Queensland botany department, Dr. Blake stated it is one of the variable forms of Macrozamia miquelii. Taking this to be true I can only comment here that the pronounced differences in the two plants make this form the "oddball" of the miquelii species!

Remembering well the great stands of these plants in various parts of the terrain of Fraser Island it appears to grow on strata that is mostly just sand (except for a thin layer of decomposed rain forest top cover.


Description:

Macrozamia douglasii develops a great symmetrical circle of leaf fronds, the largest I personally have seen was some 3 metres tall and about 4 metres in circumference. The caudex is mostly subterranean in most of the plants near the tracks, but occasionally there emerges plants of obvious great antiquity with a pronounced caudex of 1 metre in height. The central new fronds rise from the apex with the pinnae starting small and curled and developing quickly as in the other forms of M. miquelii.

Male plants have multiple cones low on the plant and also are similar as in Macrozamia miquelii. The female plants have mostly single cones developing in the axils of leaf fronds. However I did observe as many as three cones on one plant. The cones are characteristic of all Macrozamia with the seed evident, orange-red fruit visible through the green spine bearing pads that form the cone.

The seed is definitely larger than the form found nearer to Brisbane at Upper Brookfield, and the cone also is larger in size. Size of largest cones would compare favourable with the Macrozamia miquelii around the hills of Gympie, Queensland.

Habitat:

This island zamia grows on quite a few different habitats of Fraser Island, sometimes in quite moist sandy situations near freshwater swamp. Often on dry ridges beneath Banksia, eucalypt and in valleys among great stands of grass trees.

Cultivation:

The seed germinates well, even lying beneath the parent. Initial growth is single fronded with one or two more in second year up to five years, when the crown forms and hardens. At this stage the growth accelerates if the plant is treated as a container plant.

Macrozamia douglasii is variable in leaf colour. Plants generally are blue-grey in foliage, but seedling leaf colour is dark green. The gender of these plants is not the mystery it is sometimes stated. In more mature plants it is easy to pick the females because of the little seedlings growing close to the caudex around them.

Quite obviously as in all our Macrozamia, these plants are a source of food supply to the marsupials on Fraser Island. The toxins in the fruit causing no apparent discomfort to the creature.

Contributed by:

Len Butt (Text - from Palms & Cycads No. 21, Oct-Dec 1988).

External Links:

Cycad Pages, IUCN, JSTOR, Trebrown

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