One-Seeded Mercury (Acalypha monococca (Engelm. ex A. Gray) Lill. W. Mill. & Gandhi)

↑Similar Plants

Slender Threeseed Mercury (Acalypha gracilens)
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↑Habitat

One-seeded mercury is found in relatively stable, sunny habitats of near-neutral soil pH. Natural habitats include upland prairies, glades around rock outcroppings, ledges, savannas, and openings and borders in oak woodlands. It is less common than other Acalypha species in anthropogenic habitats, but it occurs along railroads, especially where they cut through otherwise similar habitat in its range.

Contrasting with most other Acalypha, which tend to be disturbance-loving species, one-seeded mercury tends to occur in persistently-open habitats, although it sometimes takes advantage of small-scale disturbances to establish.

It often occurs on rocky soils or sites where rock outcroppings limit plant growth and lead to persistent open conditions. It can also occur on sandy soils but is usually limited to sands with higher pH and absent from the more acidic soils that commonly form on sands.

There is usually little ground-level competition and only sparse overhead shade in the habitats where this species occurs.

↑Life Cycle

One-seeded mercury is a warm-season annual. Seeds usually germinate in the warmer portion of spring, and quickly establish a taproot. Plants grow slowly through the growing season, usually blooming in fall. The bloom period is long and seeds mature gradually as the plant continues to flower. Flowers are wind-pollinated.

The fewer, but larger seeds of this species, relative to other Acalypha species, help it to establish more reliably in drier, more nutrient-poor conditions.

↑Notes

USDA PLANTS call this plant "slender threeseed mercury", a name shared in common with slender threeseed mercury (Acalypha gracilens); we find this name misleading and recommend against using it. Not only does it refer to a different species that is easily confused with this one, but it is inaccurate in that this species is "one-seeded", not three-seeded as that name suggests.

↑Links & External Resources

• Acalypha monococca (slender threeseed mercury) | USDA PLANTS Database (About This Site)

• Slender Threeseed Mercury | iNaturalist (About This Site)

• Acalypha monococca | Biota of North America Project (BONAP) (About This Site)

• Acalypha monococca | NatureServe Explorer (About This Site)

• Acalypha monococca | Flora of North America (About This Site)

• Acalypha monococca | Missouri Plants (About This Site)

• Acalypha monococca (Engelm. ex A.Gray) Lill.W.Mill. & Gandhi | Plants of the World Online (POWO) (About This Site)