Lepidozamia hopei notes

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Figure 1. L. hopei at Cape Tribulation, N.Q.

A few years ago, we purchased a farming property midway between Cardwell and Tully in north Queensland, on the bank of Dallachy Creek. John Dallachy was a botanist with the original landing party who founded the town of Cardwell in 1864. Thenceforth Dallachy explored widely in the area behind Rockingham Bay, and collected many new botanical specimens, which he sent to Ferdinand Von Mueller in Melbourne, and to botanists overseas.

It was at Dallachy Creek that I really became interested in Lepidozamia hopei, often going for a walk along the creek to admire these amazing trees. In this region they seem to be confined to an area just where the creek comes down from the steep hills and flattens out on the coastal plain, a small, in between area, sandy and rocky, some L. hopei growing in the rocky bed of creeks, others on the very edge of high, perpendicular banks of the creek proper, in rich well drained soil. The plants growing among the rocks probably have their roots down into permanent water. I have found that potted plants are happy to stand in a saucer of water, but if they are neglected and dry out, the leaves will droop downwards, but as soon as they are watered, up stand the leaves again.

Dallachy Creek is still a botanical paradise, with a great variety of ferns, orchids, palms and tall rainforest trees. Bowenia spectabilis grows prolifically, but over a much greater length of the creek than does L. hopei.

The annual rainfall would be seventy to eighty inches (1780mm), but higher up in the hills, I would think the rainfall would be much greater, Tully, fourteen miles (22 km) away, receives one hundred and fifty inches (3810mm) per year) as the creek comes down in sudden, big floods, but as quickly drains away. The creek has only a small catchment, but continues to flow right through the year; in the dry season it flows under the sand in places. As L. hopei grows in the dense rain forest along the creek, photographing them is a problem. Another is the crowded situation in the rain forest. Some of the L. hopei have been measured to over forty five feet (13. 7 metres) tall, and ninety three inches (2.3 6 metres) in circumference at three feet (1 metre) from the ground. The L. hopei canopy consists of innumerable leaves to 2.5 metres (ten feet) or more long, the glossy, dark green falcate pinnae up to 12 inches (30 cm) long and one inch (25 mm) broad. The curve of the pinnae gives them a quite different appearance from a palm, with its straight pinnae. There are trees in this colony with up to four "heads" or branches, but they are only a small proportion of the mature trees. I have seen more numerous branching specimens in other colonies, possibly due to cyclone damage.

Figure 2. L. hopei in Daintree rainforest.

I had earlier observed a strange thing about these tall L. hopei - every female tree had large calloused bumps up the trunk - left, right, left, right to within five to six feet (1.5- 2 metres) of the leaves, and than it occurred to me - those were the climbing toe holes of the aborigines of the Cardwell-Tully area who would have climbed those trees for their seeds over many seasons of coning. (The aborigines of the Cairns area knew the plant as "Arumba"). They could almost have walked up those steps, cut with stone axes, many years ago. Naturally the calluses were only up the seed cone trees, and they would have known the time of year to climb for the cones before they disintegrated and before the great White-tailed Rat (Uromys caudimaculatus) got them.

The seed cones of L. hopei are massive, and one cone would have provided a good amount of food, after the usual pounding and leaching in the stream. I have often broken open these large seeds and thought how tempting they looked, but of course, they are extremely toxic in the untreated state. The aborigines of the area would probably not have climbed those L. hopei for food for the past sixty to eighty years or even more, and the six feet (2 metres) of un-notched trunk at the top of the tree may represent growth since there has been no climbing for food. My guess is that these trees could be two hundred to three hundred years old, but scientists may have better clues. Besides the really tall trees, there are lots of short or trunkless specimens, and they seem very slow to make a tall trunk. However, the leaves grow quickly, - I have measured new, emerging leaves in potted specimens growing 5.5 inches (140mm) per day !

Figure 3. L. hopei male cone.

I have counted about eighty seeds in a cone, these being mature about June each year, but very difficult to collect. On Dallachy Creek only the very tall trees seem to produce seed cones and the White-tailed Rat, and possibly other animals, really relish them. They firstly eat the bright red, fleshy outer covering of the seed, later eating into the "nut". The few small seedling plants are usually wedged in between rocks, having fallen from the parent tree and become inaccessible to predators, so that of the large numbers of seeds produced, few are able to regenerate the colony. Also, because of competition for space in the rain forest, many of these seedlings seem to stay at the two or three leaf stage for years. As far as I am aware, Dallachy Creek is the southern most point of the range of L. hopei, which extends north to about Bloomfield. Lepidozamia hopei had a confused beginning. Rigel wrote of Encephalartos Section lepidozamia in 1863. In 1865 Walter Hill described Catakidozamia from tropical east Australia (the specimen may have been sent him by John Dallachy). Water Hill later wrote of Macrozamia denisoni variety hopei, then Frederick Manson Bailey wrote of Macrozamia hopei, habitat Daintree to Johnstone Rivers, in "Flora of Queensland" 1902. The fossil records of Victoria have produced an early relative, found in 1947, and named Lepidozamia hopcites from the early Tertiary period. However Lepidozamia hopei has been establishod by L.A.S. Johnson since 1959.

A young trunkless L. hopei in my garden put out twelve new leaves in March, the leaves reaching ten foot {3 metres) long. The petioles of these leaves were three feet {1 m} long, 130 pinnae on each leaf, the pinnae twelve inches (30 cm) long by one inch (25mm) wide. The leaves are produced in one big flush just once a year. One year the whole now flush was decimated by hundreds of tiny beetles of the Anadastus species - a very disappointing experience. Though this plant belongs to tropical rain forest, I understand they are growing well in Sydney, in cultivation.

Contributed by:

Mrs. H.R. Bosworth (Text - from Palms & Cycads, No 38, Jan-Mar 1993).
Bill Snewin (Figure 1)
Lyle Arnold (Figure 2)
Mrs H. R. Bosworth (Figure 3)

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