Equisetaceae

The Equisetaceae, commonly known as the horsetail family, represents the sole surviving family of the order Equisetales and the class Equisetopsida. This group of primitive, spore-bearing vascular plants is ancient, with extinct members dating back to the Devonian Period.12

The only living genus is Equisetum, comprising about 15 species of herbaceous plants found worldwide, except in Australia, New Zealand, and Antarctica. These plants are characterized by their jointed, often ribbed stems and whorled leaves and branches. Horsetails typically grow in moist environments, though some species have adapted to drier conditions.23

While extinct horsetails included large trees, modern species are generally smaller, though some can reach several meters in height. Their stems are notable for containing silica, which historically led to their use as scouring agents. Although horsetails can be poisonous to livestock, they have also been used in folk medicine.23