Equisetum

Equisetum - Overview

The family Equisetaceae comprises one genus, Equisetum. All around the world, there are close to 15 known species of Equisetum. The most commonly occurring species in lowa are Equisetum hyemale (scouring rush) and Equisetum arvense (field horsetail).

The Equisetum in the world of Botany is most closely associated with ferns. As seen in ferns, Equisetum does not produce seeds, rather it reproduces through sexual modes via spore formation. However, in the spreading of Equisetum, spores are comparatively not as important.

The radial spread of horsetail is enabled by an extensive underground rhizome system, which can expand across 4 feet or more. The rhizomes radiate outward from the patch center, but the lateral spread of horsetail is comparatively slower in the absence of soil disturbance which pushes the rhizome pieces.

Classification of Equisetum

Kingdom: Plantae

Class: Polypodiopsida

Order: Equisetales

Family – Equisetaceae

Genus: Equisetum

Form of Growth

Equisetum, commonly referred to as “horsetails”, has a distinct growth form. Its spores are able to spread through the ground, often found in wet environments and deemed semi-aquatic. This species of plant is distinct from ferns due to its unique form of growth, consisting of roots, stems, and leaves.

The stems of Equisetum appear to be composed of many small segments, similar to the stems of rushes. These stems can either stand upright or spread across the ground. Additionally, they are reinforced with silica, making them hollow and more rigid, providing them with strength.

Leaves of Equisetum are seen in a whorl-like pattern, with them growing from the same point around the stem. Their branches also follow this same pattern. Some species have small scale-like leaves, giving the plant a leafless appearance. Other species have slender, long leaves, giving the plant a feathery look. Leaves sprout from nodes, and the base of the leaves unite around the stem, forming a collar.

The presence of a single vein in the leaves of Equisetum is a striking feature, and is believed to have recently evolved, as it is shared with lycophytes.

The Equisetum species have rhizomes which grow deep into the ground. Some of these species have strobili, which produce and protect spores for reproduction.

Commonly, this species is not very tall; their average height is close to 2 m, with the tallest they can grow being 8 m.

Also Read:

| Plant Kingdom |

| Bryophytes |

Reproduction in Equisetum

The sporophytes of horsetails reproduce both through spore production and vegetative modes.

Formation of Spores - Spores are formed on strobili or cones, which are special spore-bearing structures that project individually at the apex of fertile shoots. Primitive cones are sub-sessile and apiculate, while advanced cones are stalked with a rounded apex. In some species, an annulus (ring-like outgrowth) is also present.
Vegetative Reproduction - it occurs by two modes:

Tubers – a round tuber found in a few species is produced from rhizomes. When separated from the mother rhizome, the individual tuber is capable of growing into a new plant, thus acting as a form of vegetative propagation in sporophytes.

Each branch of Primordia possesses preformed branch primordia that develop into aerial branches and subterranean ones once the old rhizome decays.

Frequently Asked Questions

Equisetum is found on every continent except Antarctica.

Equisetum has a worldwide distribution, except in Antarctica. It is mostly concentrated in the non-tropical northern hemisphere, particularly in the northern part of North America.

What is Marestail?

Marestail (Conyza Canadensis) is an annual weed that is native to North America. It grows in a wide range of habitats, from lawns to roadsides and is known for its white, fluffy flower heads. Marestail is a member of the sunflower family and is considered a nuisance weed due to its ability to spread quickly and compete with desirable plants.

Marestal (Hippuris genus) is an aquatic flowering plant that superficially resembles Equisetum genus. The names horsetail and marestail occasionally add to the confusion.

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