Some leaves contain gold. If a tree lies above a deposit of gold then tiny traces of the element is passed through the tree and into the leaves; this means that before digging for gold, you could theoretically check the chemical composition of the leaves in an area. According to the man who made this discovery in 2013, the method is so effective that ‘some companies may already be aware of it, but have kept it quiet.’
Another recent discovery about leaves, made in 2008, is that no matter where a tree lives, the internal temperature of its leaves will be about 69.8 degrees Fahrenheit (21.4 degrees Celsius) - the best temperature for photosynthesis. In the same year it was discovered that insects use leaves like telephones; an animal that eats the roots of a tree can send a chemical warning signal through the plant leaves, so that any potential leafeaters are alerted that the plant is occupied.
It seems that there is still a lot to learn about the humble leaf.
Where does a wise man hide a leaf? In the forest.
Queensland’s gympie-gympie leaf has one of the most vicious stings in nature; a brush against it feels like being burnt with hot acid and electrocuted at the same time. The worst thing you can do with a gympie-gympie is wipe your bottom; according to one account, a soldier on military training in the bush during World War II was taken short, picked the wrong leaf, and found himself in so much pain that he ended up shooting himself.
One of the first mentions of the leaf is from 1866: a road surveyor reported that his packhorse ‘was stung, got mad, and died within two hours’. In another incident, Les Moore, a scientific officer with the Queensland government was stung across the face and ‘ended up resembling Mr. Potato Head.’
According to Australian Geographic, in the 1960s British military scientists inquired about the gympie-gympie, and were sent samples, presumably investigating its potential as a biological weapon,
New Zealand has lethal 15 foot tall nettle trees. The one case of a killer ongaonga plant occurred on Boxing Day 1961 when a hiker brushed past the well-camouflaged plant that is armed with large needles. The ongaonga’s neurotoxin caused the man’s nervous system to shut down within 5 hours.
Babe Ruth always wore a cabbage leaf under his cap to keep his head cool.
Four-leafed clovers gain their extra leaves as a result of stress.
Man's life is like a drop of dew on a leaf.
Giraffes rarely drink, as the leaves they eat contain so much water.
Some species of leaf pretend to be sick.
Variegation is caused when some of the cells in a leaf lose chlorophyll, so that they appear white. Consequently, those cells lose the ability to photosynthesize. On the face of it, that’s a clear evolutionary disadvantage, so the reason for variegation in the wild has been something of a mystery. However, a recent chance find in Ecuador may offer a solution: researchers from the University of Bayreuth noticed that the plain green leaves of a plant called Caladium steudneriifolium were far more frequently damaged by caterpillars than the variegated leaves on plants of the same species nearby.
The variegation patterns mimic the damage done to leaves by other caterpillars; in other words, the presence of variegation gives the moths the impression that that particular leaf has been previously infested by another moth, and so has already had all the nutrient sucked out of it – so the leaf appears to be saying “There’s no point eating me – I’m sick”.
Chimps in West Africa use leaves as sponges to soak up fermenting palm sap and get drunk.
In Malaysia, tea is made from the droppings of stick insects fed on guava leaves.
A folivore is an animal that mainly eats leaves.
Adam's Flannel is popularly known as 'the Andrex plant'. Its large leaves covered in soft greyish wool make ideal emergency toilet paper.
Allen's swamp monkeys go fishing with leaves. They place the leaves onto a river and pick out the fish that hide under them.