Macrozamia heteromera

Macrozamia heteromera was first discovered by Australian botanist Charles Moore during a journey in 1858 where he discovered leaf specimens of the Heteromera. However, as Moore was unable to collect any of the fruit, he did not have enough information to provide a thorough description of the plant. It was not until the year 1882 where Moore's assistant Ernst Betche had collected adequate specimens of the leaves and fruit of the Heteromera which upon receiving was named by Moore. He described the plant as having a small trunk approximately long and covered with what seemed to be a red coloured wool. Furthermore, its leaves were long, covered in long hairs and spirally twisted consisting of pinnae forked variously and simply around long. At the time, Moore had believed that there were two other variations of M. heteromera. He named the two variants glauca and tenuifolia. The glauca was distinguishable by its longer leaves that lacked rigidity and were always glaucous and glabrous. The tenuifolia's leaves were more rigid of a dark green colour. Furthermore, its pinnae forked twice and were bright red at the base. However, after a small revision in 1998 by David L Jones, the glauca and tenuifolia variants became recognised as their own species under the M. heteromera complex. The glauca variant became known as Macrozamia glaucophylla and the tenuifolia became Macrozamia polymorpha. == Taxonomy and nomenclature ==

M. heteromera was first described in 1883 by Charles Moore. This was done in the 17th volume of the Journal and Proceedings of the Royal Society of New South Wales where he described ten plants that were classified under the Macrozamia genus. Moore had named it M. heteromera after its divided pinnae that were very inconsistent in appearance. This may suggest a casual correlation that plants with divided pinnae possess a slight selective advantage in their environment. == Description ==

The Macrozamia Heteromera is a small low-trunked cycad that often grows to a height of less than 1 meter Male cones typically range from long and up to in diameter. Similarly, females range from long, wide are up to in diameter and have green and pink sections on the sporophyll. Inside the cones are red sacrotesta seeds of an irregular prism shape that is uniformly spread in the cycad. == Distribution and habitat ==

Occurring on sandy, stony and infertile siliceous soils over acid volcanics and often in dry sclerophyll woodlands, Macrozamia Heteromera is an endemic species to New South Wales. The climate of Warrumbungle is temperate and warm with a significant frequency of rainfall all year round including the driest seasons. The average annual temperature and precipitation of the range is 17.1 °C and 655mm respectively. Coonabarabran is a small town known as the 'Gateway to the Warrumbungles'. It is at an elevation of 509m above sea level with a minimum and maximum temperature of -3.6 °C and 35.9 °C, averaging once per week in winter and summer respectively. Coonabarabran has an average rainfall of 744.7mm annually, the seasonal rainfall pattern can be described as follows: Summer (32%), Autumn (23%), Winter (23%) and Spring (23%). == Toxicity ==

Cycads of the Zamiaceae family are generally toxic and produce the azoxyglycoside macrozamin. Macrozamin is composed of a primeverosa which is a disaccharide formed by glucose and xylose. == Ecology ==

The seeds from this cycad are edible after proper preparation. The macrozamin produced by M. heteromera is the result of an evolutionary defence mechanism to prevent itself from being consumed by herbivores. Some fatalities of cattle had been reported and those affected had staggered and lost control of their hindquarters. This resulted in five sheep dying within 18 to 20 hours after consumption and death continuing for three weeks resulting in 2,200 sheep dying out of the total 6,000. Farmers have used terms such as 'zamia staggers', 'zamia rickets' or 'zamia wobbles' to describe the symptoms due to cattle consuming Macrozamia seeds and leaves. Farmers had coined the term 'sheep nuts' for M. heteromera seeds in particular. ==References==