Horsetails are among the oldest members of the fern family, dating back 300 million years to the
Carboniferous Period. They are largely unchanged from when dinosaurs ruled the earth.
Field horsetails have high levels of silicon (10%!), and were once used to polish pewter and
wood.
Horsetails are found almost everywhere in North America. Like all horsetails, they are fond
of damp soil, but these also grow in fields, woods, waste places, and glades. They prefer
light shade, but will grow in full sunlight as well.
Plants: Fertile stems, which are tipped by strobili, spore-bearing
conelike structures, are pale brown (nonphotosynthetic), erect, and unbranched. They
are 6-12″ (15-30 cm) tall. They appear
early in the season and are gone by May. Sterile stems (no “cone”) are green,
6-24″ (15-60 cm) tall, 1/16-3/16″ (3-5 mm) in diameter, with 4-14 ridges. They appear after the
fertile stems have come and gone. They are highly variable, usually
heavily branched in a series of upward-pointing whorls, usually erect, sometimes prostrate. Branches are thin, shaped like a plus sign in
cross-section. Stem and branch surfaces feel rough, due to the presence of silica—tiny glasslike
spheres absorbed from the soil and deposited in the plant.
Leaves: Tiny, dark brown sharp-tipped leaves surround
the stem at nodes. They do not perform photosynthesis.
Fruits: Conelike structures that are neither cones nor fruits
appear atop the fertile stems. They are 1-1½″ (2.5-3.8 cm) long, with blunt tips.
Medical: Native Americans and early settlers made a diuretic tea
from this plant.
Edibility: The buds are eaten in Japan, but other portions of
the plant and all other species of Equisetum are toxic. Unless you are a grizzly bear, in
which case field horsetails make up about 3-5% of your diet. Black bears also consume it, despite
its low nutritive value.