Hikers, anglers and other outdoor enthusiasts are urged to keep an eye out this spring for an elusive plant that may be staging a comeback. The so-called stinging rejoinder, Aculeatus depulsio, although it is a distant cousin of stinging nettle, Urtica dioica, does not actually sting or cause a rash. It is an inconspicuous, native medicinal plant which was over-harvested in the 19th and early 20th centuries, and has been hard to find since that time. However, there is indirect evidence its population could be on the rise.
Its common name comes from the way Aculeatus depulsio works on the nervous system. When taken internally, the stinging rejoinder seems to temporarily inhibit neuronal reuptake of glutamate, an excitatory neurotransmitter, in the frontal cortex. In plain English, it makes you smarter for a short time, which explains its popularity. It does lose potency quickly, though, and must be used fresh. » Continue Reading.