Nettles

I have frequently broached the subject of nettles, and will doubtless do so again. They are ubiquitous, memorable (thanks to their never-to-be-forgotten sting), ecologically significant, conspicuous (individuals over 3 metres tall have been measured), commercially valuable - think fibres for ropes and cloth,  rich in folk-lore...and are thugs.


We are often encouraged to grow them in our gardens, but given the opportunity they will frequently form the near-impenetrable thickets with which we are all familiar. Insects which depend upon nettles have no trouble in finding bountiful quantities.

Nettles can soon create an impenetrable thicket.

Stefen Hill Pocket Park, 3 August, 2020

The list of insects dependent upon nettles is a long one and includes among the lepidoptera the Peacock (Inachis io), Small Tortoiseshell (Aglais urticae), Red Admiral (Vanessa atalanta), the Mother-of-pearl (Pleuroptya ruralis) and the Nettle-tap (Anthophila fabriciana). Many weevils and plant bugs are similarly dependent upon nettles.

Peacock butterfly feeding at Spear Thistle.

Byfield Pocket Park, 2 August, 2020

Not that nettles depend upon other organisms. Their flowers, held in pendulate, catkin-like inflorescences, are wind-pollinated and they are also able to spread via tough rhizomes (which, along with the leaves, make useful dyestuffs). Their various visitors simply use the highly nutritious leaves as a pabulum.

Urtica dioica showing the dangling strings of flowers.

Stefen Hill Pocket Park, 3 August, 2020

But how do taxonomists view them? We have two species present in Britain. All the remarks I have made so far were made with the common perennial stinging nettle, Urtica dioica, in mind but gardeners and farmers on lighter soils will also have come across the Annual Nettle, Urtica urens (urens means 'stinging or burning') but this species is rarely a problem. These plants together with their close relatives are generally placed in their own family, the Urticaceae. The late David Bellamy claimed that they were named thus because they 'urt you and indeed the Latin word urtica doesmean sting.

There are some 500 species in what appears to be a self-contained family. But life is never that simple. The Urticaceae is closely related to the Cannabinaceae family which, apart from its obvious significance in terms of drugs, is another source of important fibres.


I include a picture of cannabis for readers who, like myself, lead simple, sin-free and generally blameless lives.

Cannabis sativa; sativa means planted or grown, as opposed to wild.

Over recent years the advances made in molecular studies have turned many previously-held ideas on their heads. It appears that nettles more properly belong in the largely tropical Cecropiaceae family. Like the Cannabinaceae, the Cercopia family includes species of importance pharmacologically.

 Fruits of the Red Embauba, Cercropia glaziovii, are consumed by toucans

and sloths.

I have a suspicion that it will be many years before writers of British floras recognise the Ceropiaceae family as a component of our flora.