The Zamia plant is a primitive gymnosperm, meaning it produces seeds without flowers or fruit. It has been around for over 200 million years. Despite similarities in appearance, they are not palms. Palms are relative newcomers at 70-80 million years. They are angiosperms, a group of flowering and fruiting seed plants.
There is a lot to learn about them and we are delighted that Curtin students have shared the results of a study they conducted in September 2024.
Macrozamia riedlei is restricted to the southwest and south coast of Western Australia and is possibly the first recorded toxic plant in Western Australia. The crew of Willem de Vlamingh’s ship who visited the Swan River in 1697, became ill after eating the seeds. It is a non-flowering, cone-bearing plant attaining a height of 0.5-3.0 metres. The leaves arise at, or just above, ground level from a swollen underground stem with a fleshy tuber. Fronds are rigid, up to 2 metres long with a thick midrib and sharp pointed leaf segments. There are separate male and female plants.
Male plants bear small cones which produce pollen. Female plants bear pineapple like cones which produce seeds. The female cone measures 120–250 millimetres wide and 250–500 millimetres long, and the weight has been recorded up to 14 kilograms. The giant cones amidst the crown of palm-like fronds contain edible seeds surrounded by red sarcotesta. The seeds are consumed by birds and animals and can be a favoured part of the human diet when prepared correctly. The cones appear in May. The following autumn the cones break open releasing the bright red seeds. After lying dormant for a year, germination begins after the following winter rains.
Local Noongar names for the plant are baian, djiriji, koondagoor and quinning. Different names are applied to various parts of the plants and its products, most of which have had some uses. Fronds were used for shelter, fluff produced in the middle is like wool and has been used in baby beds and for making fire. The toxic red seeds were soaked in running water and crushed to make seed dampers. Noongar people would use the poison to stun fish in their fish traps. It just so happens that mullet are running in the Swan River in March when seeds break open from the cone.
Birds and mammals are attracted to the reproductive cone structure and insects are involved in the pollination of the female plant. Some birds eat the fleshy part of the seed cone, other birds known to eat the seeds include the emu, common bronzewing pigeon, cockatoos, silvereye, grey butcherbird and raven.
