Equisetum telmateia Ehrh.
A herbaceous perennial with hollow, ridged, leafless, jointed stems. Stems of two types: the sterile ones between 30 and 100 cm tall, pale green, with 15 to 40 ridges. Joints covered by green sheaths 5 to 10 mm long, which have brown teeth 3 to 10 mm long, and bearing whorls of 20 to 40 ribbed, jointed linear branches up to 20 cm long. The fertile stems are whitish, between 15 and 45 cm tall, unbranched, soon withering, and producing apical cones 5 to 10 cm long, 1 to 2 cm broad, which bear the spores.
Local: Rare in Gibraltar. Found on well-watered cultivated plots around town, mainly in the Trafalgar interchange.
Global: Found in wet habitats throughout the northern hemisphere.
Spores produced between December, January, February, March, April, May and June.