Hi Lian,
I think that you could have precised what poison ivy looks like
physically because there are many plants/weeds that looks like it.
That way, an alien could know exactly what it looks like and avoid
it.
You can also specify that poison ivy could be used in herbal medicine
and the people that actually grow them know what they are doing but
normal people shouldn't try it out themselves. The alien could then
have a full understanding that poison ivy is not just there to be a
pest, but could also be used in a good way.
Other than those small details, your explanation is very concrete and
clear. Good job.
> People do not grow poison ivy in their gardens for a great many
> reasons. First of all, this particular plant is know to cause major
> rashes at the slightest contact with our skin. This reaction is caused
> by the urishiol oil that this plant secretes as its natural defence
> mechanism. On its own this oil is harmless, and it is not actually a
> poison but as it comes into contact with our skin, our own immune
> system recongnizes it as an allergen and reacts by flaring up and by
> producing a liquid know as lymph to try and wash the oil off. That
> being said, it would be highly unpractical to grow poison ivy in your
> garden because it would simply cause you a great deal of discomfort to
> walk in your garden. Secondly, poison ivy is considered to be an
> unwanted weed by our society. Mainly because of its awful side effects
> and because of its appearance. In the wild, it is usually found in a
> small bush, and has no flowers. Therefore, since the plant is not
> aesthetically appealing, theres is no reason to plant any poison ivy.
> Furthermore, people would not be able to actually enjoy gardening
> without fear of coming into contact with the plant, which is hard to
> do when you are surrounded by it. Of course, one could wear protective
> clothing, but the oil would still cling to the fabric and everything
> would have to be washed, without touching the oil, which is extremely
> difficult and almost impossible considering that it is odourless and
> colourless.Thirdly, gardens serve the purpose of adding value to a
> property. If it were to have any poison ivy in it most people would
> not want to live in it. In fact since it has weed like properties, if
> it is found in an area it is likely to grow back even if you try to
> remove it. To add to that thought, people with children would stay far
> away from the houses with poison ivy in fear that their kids will
> accidentally go play around in the bushes, so no real social event can
> take place in that garden, which is not to great for meeting new
> people or making friends.