You pick up a newspaper and a small catalogue falls out, full of wonderful-sounding household gadgets and cleaning substances, often 'designed by NASA', or 'As used by the SAS'. As you look through it, you might even find an advertisement for the amazing 'Neptune Plant'.

To read the flabbergasting description, you might begin to wonder what kind of wonderful plant this is. It 'comes from the bottom of the ocean', 'repels insects', and perhaps most surprising of all, it is said to survive and remain green for 'years' without watering. It is so unusual that 'scientists have not placed it in any botanical category'. Now, this might come as a shock. For hundreds of years, taxonomists have been collecting, naming and classifying new species as they are discovered. Why, then, have they ignored this one? Can the claim be true?

Well, yes and no. They haven't classified it in any botanical category, because quite simply botanists have no interest in such things - the Neptune plant, or 'air fern', is not a member of the plant kingdom at all! In reality, it is composed of the remains of tiny marine animals called Sertularia argenta, related to jellyfish. It's also very unfair to imply that taxonomists are completely baffled by this strange 'plant', when they classified it as long ago as 1758. But in advertising, as in war, the first casualty is often truth.

So, what exactly is this creature, then?

Well, to our much-maligned taxonomist, our little friend is known precisely as follows:

The creatures live joined together in a structure known as a colony. Within the colony are distinct individuals known as polyps. Different polyps have different roles - some may be reproductive, while others are concerned with feeding. One interesting thing is that polyps can pass nutrition amongst themselves throughout the structure of the colony, while still remaining individual creatures. When a 'Neptune Plant' is bought, the product actually sold is the skeletal remains of S. argentea, whose shrubby look and feel might not seem out of place at Kew or the gardens of Versailles. Despite this, after being trawled up from the bottom of the North Sea the silvery 'foliage' is often dyed green, to make it look more like the usual houseplant. For further biological information including a picture, visit the Marine Life Encyclopedia.

In the UK in March, 2008, complaints were made to the Advertising Standards Authority against one of the companies marketing S. argentea in this way. The complaints hinged on the issue of whether it was a real, living plant as the company stated or something else. The ASA judged this to be a misleading claim - as most untrue statements are! The ASA also ruled that the claims made that these skeletal remains 'emit fragrant secretions which drive insects away, especially flies' are unsubstantiated. The company in question were told not to use this advertisement again, but similar claims can still be found elsewhere.

Perhaps the moral of the story is that a little scepticism is always of use when poring over the advertising columns.