Goosefoot (Chenopodiaceae family):
Atriplex patula L.
EPPO code:
ATXPA
Other names:
Halberdleaf orach, , spear saltbush

Species information

Lifecycle:
Annual.
Propagation:
Reproduces by seed , has separate male and female plants (dioecious).
Emergence:
Emerges in the spring and is one of the first summer annual weeds to emerge, often before lamb’s-quarters.
Habitat:
In cultivated fields it is most often found on heavier textured soils but will exist on many soil types.
Competitiveness:
No published data exists on crop yield losses but presumably similar to its very competitive cousin, lamb’s-quarters.
Resistance:
No confirmed cases of resistant populations.

Identification clues

Leaves

Cotyledons:
Linear with a very short petiole and a rounded tip.
Young leaves:
Oval-lanceolate, often egg-shaped and lightly coated with white, mealy powder.
Mature leaves:
Irregular toothed margin, green with two prominent basal lobes, the base distinctly triangular. Lightly covered in white mealy powder.

Mature plant

Stem:
Stems are wiry and smooth. Opposite leaf orientation (2 per node) on the stem.
Flowers and seed heads:
Very small inconspicuous flowers in dense green clusters. Female plants produce irregularly shaped seed pods enclosed by diamond shaped bracts.
Roots:
Taproot.

Often mistaken for

I know it's not Lamb's-quarters because Spreading atriplex has much narrower leaves with two prominent sharp basal lobes compared to lamb’s-quarters much broader triangular shaped leaf. Spreading atriplex also has a wiry stem with opposite leaf orientation compared to the much more branched lamb’s-quarters with its alternate leaf orientation.

I know it's not Fig-leaved goosefoot because Fig-leaved goosefoot leaves look very similar as they too have the prominent basal lobes. However, the leaf shape above those basal lobes is rectangular but with a round apex. With spreading atriplex, the leaf blade above the basal lobes is triangular with a pointed apex. In addition, the basal lobes of fig-leaved goosefoot are rounded while those of atriplex are pointy.

Seedling plants at the 2-leaf stage during the first week of May
Seedling plants at the 2-leaf stage during the first week of May.
The first leaf of spreading atriplex (left), compared to a leaf typical of the 8–10 leaf stage of growth (right)
The first leaf of spreading atriplex (left), compared to a leaf typical of the 8–10 leaf stage of growth (right).
Although the orientation of leaves may appear alternate on young seedling plants, leaf orientation on mature plants is clearly opposite
Although the orientation of leaves may appear alternate on young seedling plants, leaf orientation on mature plants is clearly opposite.
Spreading atriplex has two distinct lobes at the base of its leaf (right) differentiating it from common lamb’s-quarters (left)
Spreading atriplex has two distinct lobes at the base of its leaf (right) differentiating it from common lamb’s-quarters (left).
Clusters of flowers with their distinctly diamond shaped bracts
Clusters of flowers with their distinctly diamond shaped bracts.