Virginia Tech Weed Identification Guide

Mayweed Chamomile: Anthemis cotula

Weed Description:  Winter or summer annual with finely dissected leaves that may reach 2 feet in height.  Primarily a weed of landscapes, nursery, and some agronomic crops that is found throughout the United States.

 

Seedling:  Stems below the cotyledons (hypocotyls) are green and become maroon with age.  Cotyledons are thick and smooth, approximately 7 to 8 mm long.  The first true leaves are opposite, but all subsequent leaves are alternate.  All true leaves are thick and finely dissected with some short hairs.

Leaves:  Alternate, finely dissected, approximately 3/4 to 2 1/2 inches long and 1 inch wide.  Leaves emit an unpleasant odor and may have some short hairs.

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Stems:  Erect, branching, usually without hairs.

Roots:  Taproot and fibrous root system.

Fruit:  An achene that is approximately 1.2 to 1.8 mm long.

Flowers:  Occur in solitary heads at the ends of branches.  Flowers are approximately 2/3 to 1 1/3 inches in diameter and are white (ray flowers) with yellow centers (disk flowers).  White ray flowers have 3 distinct teeth. mayweed6-1.jpg (87489 bytes)
mayweed6-1d.jpg (35728 bytes) Identifying Characteristics:  Plants with finely dissected leaves that emit an unpleasant odor and have white flowers with a yellow center.  Mayweed chamomile may resemble Dogfennel (Eupatorium capillifolium) when in the seedling stage, however dogfennel seedlings have petiolated cotyledons and hairy stems.  Pineapple-weed (Matricaria matricarioides) also has similar characteristics, but has green flowers and emits a pineapple-like odor when crushed.