Montana Field Guide

Smooth Goosefoot is an annual with erect, simple, or highly stems 2-3 (8) dm high. The alternate leaves are linear with entire margins, single veined, glabrous, up to 3 cm long. The small, green flowers are grouped in remote clusters in simple or branched spikes. Each flower lacks petals but has 5 glabrous sepals and 5 stamens. The 1-seeded fruit is compressed hemispheric and is relatively large; 1-2 mm across, exposing a jet-black fruit at maturity that readily separates from the pericarp (fruit wall).

Fruiting occurs in late June-July.

Chenopodium fremontii also has narrow, entire-margined leaves, but they are larger and have three veins rather than just one. Chenopodium leptophyllum is similar but its leaves are grayish-mealy rather than nearly glabrous. Hitchcock et al. (1964, Vascular Plants of the Pacific Northwest Vol. 2) treats Chenopodium leptophyllum and C. subglabrum as conspecific.

Smooth goosefoot grows in extremely loose, sandy soils and tends to occupy early successional, sparsely vegetated habitats. The unconsolidated sandy substrate is nutrient poor and droughty. In Montana, it inhabits sand dunes and occasional river sandbars or sandy terraces. In Alberta, Saskatchewan and Manitoba, the species is generally found on south- or west-facing, actively eroding slopes at the edge of stabilizing sand, and sometimes in dune slacks (Smith and Bradley 1990). Associates at a site in Harding County, South Dakota include Sporobolus cryptandrus, Chenopodium ambrosioides, Ambrosia acanthicarpa, Oryzopsis hymenoides, and Rumex venosus. (Legumes were noted to be absent.)

Smooth goosefoot is an annual that grows in habitats with loose sand deposited by wind or water. Populations are small, and are likely to migrate in position over time (Heidel 1990). The largest populations are in areas of finer and more compacted sand, and it rarely grows in highly unstable sand. It may occur in stabilized sand, however, populations in these habitats are always small. It cannot survive where succession leads to a continuous vegetation cover, and is vulnerable to competition from weedy exotics such as Melilotus officinalis and Euphorbia esula.

Like most members of the Goosefoot Family, this species is tolerant of both xeric and alkali-impregnated conditions (Smith and Bradley 1990). Like other species of the genus, it is wind-pollinated and is likely to have seeds that can survive one or more years until they germinate. It produces relatively few seeds per plant, so seedling establishment is presumed critical in its life history. Smooth goosefoot is an annual; populations develop from seed each year, and therefore population size is likely to fluctuate widely between years.

Populations of the species are dependent on areas of active, drifting sand, most of which are now under cultivation. Stabilization of the remaining sand dune habitat is also a problem. Wallis and Wershler have suggested lack of fire as a major factor in stabilization of southern Alberta sand dunes (Smith and Bradley 1990; see also Lesica and Cooper 1998). Grazing is also thought to be important in maintaining a portion of unstabilized sandy habitats within these areas. A combination of fire and grazing during appropriate seasons is most effective in keeping blowouts active (Smith and Bradley 1990). Several sites in Alberta are leased for grazing, and include the largest provincial populations of the species.

In Alberta, one of the principal threats to this species is the invasion of non-native plants - particularly crested wheatgrass and sweet clovers - along oil and gas access roads and well-sites (Smith and Bradley 1990). Noxious weeds like Euphorbia esula (leafy spurge) can take over this species' habitat and already pose a threat elsewhere in its range (Smith and Bradley 1990). Tamarix chinensis (tamarisk), which has major impacts on river sandbar habitats, is invading the Powder River basin, where smooth goosefoot was first collected in Montana, in 1973.

STATE THREAT SCORE REASON
Reported threats to Montana's populations of Smooth Goosefoot (Chenopodium subglabrum) are currently assigned as unknown. Discussions within the Montana Native Plant Society Threat Ranking Subcommittee indicated there are likely significant threats to Smooth Goosefoot; however, specific threat information needs to be brought forth (MTNHP Threat Assessment 2021).