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Poison and medicine

Plants started to use insects for pollination and the first flowers appeared.

The people who study fossils say that about 65 million years ago, around the time when the dinosaurs went extinct, there were relatively few plant species on earth, compared to today. The same with the insects.

The plants at that time were mostly ferns and cycads, which used water and wind for pollination. The insects were things like cockroaches and dragonlies which did not need flowers to survive.

Then something amazing happened. Plants started to use insects for pollination and the first flowers appeared. By using insects as agents for this crucial job, plants were able to colonise land away from the water, and evolved flowers of different shapes and colors to attract them. With this abundant and diverse new food source, insects themselves exploded in diversity.

The truth is that all this actually happened simultaneously and not one after the other. And this was the start of a very long relationship between plants and insects, called co-evolution.

The problem was that most of these new insect species were plant eaters, so plants developed chemical defences to save themselves from extiction. Some acted as poisons and others as repellents, as long as they kept insects away!

Over the years, humans have learned to use these as poison, medicine, insect repellents and food spices. Many of the herbs we use in our food belong in the mint family, renowned for its aromatic plants, originally designed to repel insects!

The paintbrush lily (Scadoxus puniceus) grows in shady spots in our bushveld and forests. It is a bulbous plant which appears suddenly after rain, after spending winter underground. It belongs in the Amarillys family, which contains many poisonous plants like Clivia and Crinum (river lily).

Although the plant is poisonous, and deaths had been reported from ingesting it, the bulb is widely used in traditional medicine. It is used for coughs and gastro-intestinal problems, as well as a part of medicine taken during pregnancy to ensure a safe delivery. It seems there is a fine line between poison and medicine!

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