Southwest Colorado Wildflowers, Equisetum arvense

Equisetaceae are the sole survivors of a line of plants going back three hundred million years; members of this family gave rise to many of our coal deposits. Equisetaceae are widespread through the United States and in the semi-deserts, foothills, and mountains of the Four Corners they are commonly seen near streams and in damp forests and meadows.

The genus name, which means "horsetails", was given by Linnaeus in 1753.

Equisetum arvense (Horsetails)
Equisetaceae (Horsetail Family)

Montane, subalpine. Streamsides, wetlands. Spring.
Lizard Head Trail, June 19, 2004.

This very common, fern-related ancient plant loves wet areas but is also found in seasonally moist areas. Pictured at left are the sterile stems that spread from underground roots forming extensive patches. The sheaths around each node-branching are diagnostic. The plant feels rough to the touch because of its high silica content.

"Arvense" is Latin for "field".

Equisetum arvense (Horsetails)
Equisetaceae (Horsetail Family)

Montane, subalpine. Streamsides, wetlands. Spring.
Near Forbay Lake Trail, July 12, 2007.

Equisetum arvense (Horsetails)
Equisetaceae (Horsetail Family)

Montane, subalpine. Streamsides, wetlands. Spring.
Shearer Creek Trail, May 17, 2006.

The brown, fertile, unbranched stem bears the reproductive sporangiate cone at its top. The stem and sporangiate cone grow in the very early spring and wilt in a few days; large patches of branched sterile stems, such as those pictured above, remain through the fall.