Flower:

One to numerous tiny flowers are tightly packed in round clusters (glomerules) in leaf axils along most of the stem. Flowers are either pistillate (female) or perfect (both male and female parts). Both lack petals, have a round, green ovary with a 2-parted style at the tip; perfect flowers usually have a single stamen, sometimes two.

Cupping the flower is a green calyx with a single lobe that is green, leaf-like, and twice or more as long as the flower. The calyx and stalks may be sparsely white-mealy when young, becoming smooth.

Leaves and stems:

Leaves are alternate, ½ to 2½ inches long, up to about ½ inch wide, triangular to arrowhead-shaped in outline, the lower leaves with a pair of lobes near the base, sometimes with 1 or 2 additional smaller lobes or large teeth, and the upper leaves mostly lance-elliptic, unlobed and reduced to bracts. Surfaces are sparsely white-mealy when young, becoming smooth with age. Lower leaves usually have the longest stalks, becoming short stalked to stalkless on the upper stem. Stems are multiple and branched from the base, green to reddish, finely ribbed, ascending to spreading, sometimes  prostrate but rising near the tip (decumbent).

Fruit:

Fruit is a dry seed enclosed in the persistent ovary shell (pericarp) that matures from green to gray-brown. Seeds are flattened oval, 1 to 2 mm long, lightly pitted on the surface.

Notes:

Nuttall's Povertyweed, sometimes known as Blitum nuttalianum, is fairly common in the western half of North America from Mexico to Alaska, and reaches the eastern fringe of its US range in Minnesota, though it's only been recorded here twice and not since 1944. Farther east it is considered introduced, showing up along roadsides, farm fields, and other disturbed areas; in its native range it is often found in alkaline, clay soils. It is similar to some of the related Chenopodium species, which have 5 calyx lobes of more or less equal size, where Monolepis has only one lobe that is rather leaf-like and may be taken for a bract. If you happen to spot this species in Minnesota, congratulations—you'll have moved this species off the Historical list!