Botanizing in the abode of our chlorophylled friends poses hazards, and any earnest seeker wanting to be acquainted with plants is advised to: (i) have prior knowing of what is hazardous; (ii) pay attention when out in the neighbourhood of plants, and; (iii) use pre-emptive protection.
PLANTS THAT INFLAME
Crushing leaves to get the scent for identification purposes is a admirable gesture that shows that one is serious about learning plants, but there are some plants that one should learn before learning them. YOU HAVE TO KNOW. Learn of plants that can cause allergic (usually skin) reactions. Some people may be sensitive to members of the Mango family. Some plants like the Australian Cashew is probably going to cause blisters regardless, if you get the juice on yourself. Some plants can cause blindness if you get their sap into your eyes.
The fruit wall of the Australian cashew nut can cause severe blisters to the mouth and the sap of all parts of the plant can be be a skin irritant. The same applies to raw Cashew nut kernels. To know the Australian Cashew Nut tree, watch out dor black resin stains on bark and also blacken dots on leaves where there are wounds. Another member of the mango family, the Sumac (Rhus taitensis) can cause skin reactions in sensitive people.
PLANTS THAT CAUSE PAIN
The most famous, or infamous example is the Stinging Tree (Dendrocnides moroides). YOU HAVE TO KNOW. Seal the image of how the Stinging Tree looks in your psyche and never, ever forget. Or you’ll never forget anyways when you encounter it’s hypodermic power! If you can, have some tape available. It might help you remove any needles stuck inside but nothing is going to take away the pain. The Shiny Stinging tree is a bit more problematic because it is less easy to remember, but try.
Thorny and prickly plants will also inflict damage. The lawyer vines of Far North Queensland all have free-hanging flagella (see above picture) lined with hooks that will catch onto clothes and flesh. If you get caught in these cirri, reverse gingerly. Don’t pull against it. Sounds common-sensical but people do all sorts of stupid things in the bush, like I have. I jumped up to grab a sprig of a Coral Tree (Erythrina variegata) and lacerated my hands. Enthusiasm can be blinding to one’s sensibility. Paying attention pays.
I know of an enthusiastic biologist who knew that the fruits of the Stinging tree could be eaten (and he is right!) and popped some fruits into his mouth. He was very quiet after that for some time. The stinging hairs need to be wiped off the fruits before eating. A little knowledge can be a dangerous thing!
Some plants do not sting or cause extreme pain, but can cause a bit of irritation. The hairs on the fruits, stems or leaves of certain plants can cause mild irritation, some which can last for days until the hairs make their way out of your body. So be careful when you handle bamboo, and some hairy fruits. The seedpods of the Burney Bean (Mucuna gigantea) and the leaves of the Davidsonia Plum (Davidsonia spp.) can sometimes be coated with fine irritant hairs.
PLANTS THAT POISON
There are way too many to illustrate here fully. Simple rule: NEVER EAT PLANTS YOU DON’T KNOW. If you feel you will die of curiosity not eating them, get a positive identification first. At least someone will then know what killed you, if they got it wrong. Don’t take a risk with something you only think you know.
The Septic Fig is an interesting case for a fig as most figs are edible. As the name suggests, it is one plant you shouldn’t eat, even though most figs are edible.
Native species of macadamia trees (now all in the genus Lasjia) should not be eaten as well, even though they are close relatives of the Macadamia nut.
The Finger Cherry (Rhodomyrtus macrocarpa) is another interesting case. Even though the fruits of this plant is technically edible, both adults and children have gone blind eating the berries. Talking to some aboriginal people, I have found that even they are careful with this plant. So, while this blog attempts to document the edibility of some of the plants, I do not assume any responsibility of anyone who decides to ingest any plant and falls ill.
Many of the so-called walnuts (members of the Lauraceae) can be eaten but only with proper preparation. Just don’t do it, no many how enticing the fruits look. The same goes for Black Bean (Castanospermum australe) and cycads (Cycas and Lepidozamia).