Rough horsetail

Rough horsetail, a rhizomatous plant native to North America, is easy to recognize by its upright, stiff, jointed stems. Rough to the touch, these stems can grow from about 30 cm to 1 m tall. Their colour ranges from dark green to grey-green, and they are marked with lengthwise ridges.

The leaves are reduced to a brownish sheath that encircles each node. In this species, the stem does most of the photosynthesis, producing the energy the plant needs to grow.

Rough horsetail does not produce flowers, since it belongs to the group of pteridophytes (plants such as ferns). It has vegetative stems as well as fertile stems; the fertile stems bear spore-producing cones at their tips, which contain the spores.