The photo is of a small horseweed plant. The leaves are green, hairy, and linear to lance-shaped with smooth to toothed margins.

Horseweed (marestail) – Conyza canadensis

Conyza canadensis (L.) Cronq.

Asteraceae (Aster family)

MI Status

Native

Life cycle

Erect winter or summer annual.

Leaves

Cotyledons are egg- to spatula-shaped and hairless. Seedling leaves initially develop from a basal rosette; mature leaves are alternate and numerous, and crowded along an erect central stem. Leaves are hairy and linear to lance-shaped with smooth to toothed margins, gradually becoming smaller toward the top of the plant.

Stems

An erect, hairy central stem arises from a basal rosette, then branches to flower, reaching up to 7 feet tall. Flowering branches resemble a horse’s tail.

Flowers and fruit

Numerous clusters of small, white flower heads are found on many short branches near the top. Each seedhead can produce thousands of small seeds; each seed is enclosed in a single-seeded, wind-dispersed fruit.

Reproduction

Seeds.

The photo is of a small horseweed plant. The leaves are green, hairy, and linear to lance-shaped with smooth to toothed margins.
Horseweed plant
The photo is of a horseweed flowerhead. The white flowers are in numerous clusters.
New horseweed flowerhead
The photo is an up close image of a horseweed flowers. White flower heads are found on many short branches near the top of the plant.
Horseweed flowers
The photo is of a horseweed rosette. Seedling leaves initially develop from a basal rosette.
Horseweed rosette

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