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Weed Identification

mat amaranth

Family

Amaranthaceae

Scientific Name

Amaranthus blitoides

Synonyms (former Scientific Names):

Amaranthus graecizans

Habit

Prostrate pigweed tends to spread in multiple directions from the taproot system. They develop a mat across the soil. Prostrate pigweed spreads only by seeds.

Leaves

Leaves are alternate in arrangement, oval and approximately 1/2 inch in length. They are wider at the tip than at the petiole.

Identifying Characteristics

The stems of prostrate pigweed may be light green to reddish purple and are smooth. The first leaves of the plant are wider at the apex, and are slightly magenta on the underside.

Flower Seed Head

Flowers of prostrate pigweed are monoecious and appear from June through August. The flowers are small and green and appear on leaf axils.

Seed Fruit

The seeds of prostrate pigweed are glossy and black. They are rounded in shape and convex on the sides. They are approximately 1.5 mm in diameter.

Where Found

Prostrate pigweed is found throughout North America, in almost every state. It is most commonly found in disturbed or cultivated soil and is most excessive in the western United States

Growth Habit

prostrate and nonwoody

Thorns or Spines

not present

Approximate Flower Diameter

nickle

Dominant Flower Color

green

Leaf Shape

lance

Leaf Arrangement

alternate

Leaf Margin

entire

Leaf Structure

simple

Leaf Stalk

shorter than leaf

Root Structure

taproot

Life Cycle

summer annual

Plant Type

Herb