Equisetaceae: Horsetail Family. Identify plants and species.

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Equisetaceae: Horsetail Family Plant Identification Characteristics.

Equisetaceae
Plants of the Horsetail Family

      The horsetail produces two different stalks. One is the fertile "joint-grass", the other is the sterile "horse-tail." The fertile stalk produces a cone-like structure at the top, which is covered with spore-producing scales. The spores are wrapped with small bands. These bands unwrap in dry weather to function as a parachute to carry the spores on the wind. Multiple spores frequently become entangled and travel together. The spores germinate into a thallus, cross-fertilize, then develop into a new plant. The word thallus is used to describe a plant part that is not differentiated into leaves or a stem.

      The Horsetail family is small, comprised of 1 genus and 23 species worldwide. In earlier times this group was much larger and more diverse, with many species growing into giant trees. These ancient plants formed a significant portion of our coal deposits. Some deposits consist principally of compressed masses of spores. This rock is called "cannel". It can be cut and polished for ornaments.

      Today there is only one tree-like species of horsetail. It is a native of the American tropics and grows to about thirty feet tall. The horsetails have an abrasive quality to them because they absorb silica from the soil to give strength to the plant structure.

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Equisetum arvense. Field Horsetail. Photographed in the Methow Valley, Washington.	Equisetum arvense.Field Horsetail. Photographed in the Methow Valley, Washington.
Equisetum sp. Horsetail. Photographed along the northern California coast. Other species across North America are similar in appearance but often smaller in size.	Equisetum sp. Sunlight shining through horsetail stalks.