common lambsquarters

Common lambsquarters is an annual plant in the family Amaranthaceae. It is native to Europe, Asia, and North Africa. It has been widely cultivated as a grain, a leafy vegetable, and an animal feed. It readily escapes cultivation. It now occurs throughout the world on every continent except Antarctica, in every state in the United States, and in every province in Canada except Nunavut. It occurs in every county in Minnesota.

Common lambsquarters is considered a weed in some areas. It is fast growing and highly competitive, it tolerates a wide range of soil types and environmental conditions, and it is highly resistant to insect pests and disease. It can cause significant crop losses in corn, soybean, and sugar beet fields.

Common lambsquarters is a fast-growing, annual forb. It rises on a single stem from a deep taproot and a shallow fibrous root system. It is usually 4″ to 59″ (10 to 150 cm) in height, rarely taller. It is erect at first but unless it has other plants to lean on it becomes recumbent due to the weight of the foliage and fruit.

The stem is branched and green or red.

The leaves are alternate. Lower stem leaves are triangular or diamond shaped, 1¼″ to 2¾″ (3 to 7 cm) long, and ¾″ to 2⅜″ (2 to 6 cm) wide. The margins are toothed or lobed. Upper stem leaves are lance-rhomboid shaped, ⅜″ to 2″ (1 to 5 cm) long, and ⅛″ to ¾″ (0.4 to 2.0 mm) wide. The upper surface is waxy, white mealy in appearance, and unwettable. The lower surface is whitish.

The inflorescence is a short, dense spike of small flowers at the end of the stem and branches, and rising from upper leaf axils. The flowers are greenish-white and only about ⅛″ (2.5 mm) in diameter. There are 5 outer floral leaves (sepals), together called the calyx, no petals, 5 stamens, and 3 styles. The calyx is white mealy. The stamens have yellow anthers. The styles are short and are fused at the base, separated at the tip.

The fruit is a small black seed contained in a thin, bladder-like, seed capsule called an utricle.

Sources

2, 3, 4, 5, 7, 22, 28, 29, 30.