Horsetails are included in class:

Explanation

Horsetails are classified under the class Sphenopsida, also known as Equisetopsida. This class is characterized by jointed stems, scale-like leaves arranged in whorls, and the presence of silica in their tissues, giving them a rough texture. This group comprises a greater number of fossilized plants compared to living species. Currently, only a single surviving genus, Equisetum, is found within this sub-division. These plants develop from rhizomes, which give rise to two types of aerial stems i.e., fertile and sterile.