Stinging Nettle

Urtica dioica

Common Name: Stinging nettle (Tall nettle, Slender nettle)
Scientific Name: Urtica dioica
Family: Urticaceae
Growth Form: Herb
Native Range: Northern Europe and Asia
Invasive Range: Throughout the U.S., except for southern Florida
Introduction: Brought by settlers as a medicinal plant.  The stinging nettle reproduces both by seed and rhizome, it can spread up to 2.5 m (8 ft.) per year. 
Description: ·Leaves: Opposite, deeply toothed, simple, egg-shaped or lanceolate, occasionally with heart-shaped bases, tip points sharply.  5-15 cm (2-6 in) long.  Stinging hairs and shorter bristled hairs found on underside.

·Stem: Erect.  Green.  4 sides, ridged at angles.  Covered in stinging hairs.  Bristled hairs may or may not be present.  Can grow up to 2 m (6 ft.) tall.   

·Flowers: Present from May to October.  Small, greenish-yellow.  Densely clustered from leaf axils.  Male and female clusters can be found on same plant. 

·Fruit: White or brown oval shaped achene, 1-1.5 mm long.  Single seed enclosed within. 
Threats: The stinging nettle is considered a weed.  It produces a large amount of seed and is difficult to eradicate. 
Fun Facts: The spines of the stinging nettle contain histamine and formic acid.  As a result, they normally cause pain upon contact with human flesh.  But, when they touch tissue that is already in pain, these chemicals act as a counterirritant, reducing discomfort.  The juice of the stinging nettle is used to treat insect bites and, ironically, nettle stings.
Plant (note the gloves worn to prevent stings)