THE METROPOLITAN NATURALIST
MORE FLOWERING PLANTS
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The Nettles (genus Urtica), and their relative the Wood Nettle (genus Laportia), are often felt
before they are seen. Nettles have stinging hairs, which, like jellyfish, inject a poisonous
liquid that causes a sting and sometimes a rash. The sting and rash usually last only a few
minutes. These are common plants of damp woods, often growing along hiking trails where
unlucky hikers brush against the stinging hairs.

There are several species of Nettles in the genus
Urtica. Gray's Manual of Botany listed six
species, Britton and Brown's An Illustrated Flora of the United States and Canada listed 4
species. The different species are similar in appearance and all have stinging hairs. Nettles
in our area include the Stinging Nettle (
Urtica dioica) and the Dwarf Nettle (Urtica urens).
Urtica dioica has a variety indigenous to the United States as well as varieties that were
introduced from Europe. The Dwarf Nettle was probably brought here from Europe. Nettles of
the genus Urtica are distinguished from the Wood Nettle (genus
Laportea) by opposite
leaves (the Wood Nettle's leaves are arranged alternately on the stem).

Nettles have a long history of use in traditional medicine and as a food plant. The poisonous
sting is neutralized by cooking, so young nettle plants, before they become too tough and
stringy, can be boiled like spinach and eaten. A pair of garden gloves will protect your hand
from the sting when collecting the plants.

In traditional medicine, the sting of the nettle has been used for rheumatism and other
autoimmune and allergic reactions, and to relieve pain. In a procedure called urtication, the
plants were used to whip the patient, causing the plant to sting. Pain relief might have come
from the nettle's painful sting distracting the patient from their own pain.
NETTLES (Urtica sp.)
Urtication or a tea made from the dried nettle herb have been used to treat asthma and hay fever. The roots of the
Stinging Nettle may be useful as a treatment for benign prostate hyperplasia and to help control blood glucose
levels in type 2 diabetes.
The Stinging Nettle (Urtica dioica) has been extensively studied in clinical trials and analyzed chemically. The
medicinal properties of this species might also apply to other species of nettles, and they often seem to have
been used interchangeably in traditional medicine. The Stinging Nettle (
Urtica dioica) is used to treat
rheumatism, asthma, coughs, benign prostatic hyperplasia, and hyperglycemia, among other things.
The stinging hairs of the nettles have a bladder-like base. The contents of this bladder-like base are injected
when the hair is touched. Acetylcholine, histamine, formic acid and 5-hydroxytryptamine (serotonin) have been
isolated from the stinging nettle (
Urtica dioica) and Dwarf Nettle (Urtica urens).  
Stinging Nettle with flowers at Patuxent River State Park
Stinging Nettle at Patuxent River State Park
Stinging Nettle at Patuxent River State Park
Nettle at Patapsco Valley State Park
Nettle at Patapsco Valley State Park
Nettle at Patapsco Valley State Park
Stinging Nettle with flowers at Patuxent River State Park.
The serrate, or toothed, leaf of a stinging nettle at Patuxent River State Park.
Nettle at Patapsco Valley State Park