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Manitoba Museum

Four O'Clock (Nyctaginaceae)

Sand Verbena

Tripterocalyx micranthus (Torr.) Hook.

Members of this family have flowers that open in late afternoon, hence the common name. Sand Verbena is a short-lived plant whose seeds stay dormant in the soil until spring conditions are right. Germination occurs when there is enough moisture over a long enough period of time. Pollinators of this species have not been documented. However, its white colour, tubular shape, and opening time suggest that flowers may be adapted for night-time moth pollination.

Flower Colour:

  • White

Flowering Season:

  • Spring

Flowering Months:

  • June
  • May

Canadian Rarity Status:

Protected under Canada’s Species at Risk Act and Saskatchewan’s provincial Wildlife Act, and is considered “at risk” in Alberta. The collection of wild plants and seeds is illegal on public lands.

Physical Appearance:

This annual grows 20 – 50 cm tall. Its many branches spread along the ground. The paired, rounded leaves are 2-6 cm long, with prominent veins and smooth edges. Tiny flowers (5 mm wide) are arranged into dense clusters surrounded by a ring of bracts. Each one has five petal-like lobes forming a narrow tube. When in fruit, the tube base becomes a papery wing-like structure with 2-3 lobes, which helps with dispersal.

Similar Species:

Sand Dock (Rumex venosus Pursh)

Gardening Notes:

Do not purchase wild-collected seeds or plants. Seeds and/or plants from nursery-raised stock may be available.

Canadian Distribution:

  • Alberta
  • Saskatchewan

Prairie Types:

  • Mixed Grass Prairie


  • Prairies
  • Sand dunes
  • Sand Flats

Moisture Conditions:

  • Dry

Light Preference:

  • Full Sun

Soil Preference:

  • Sand
Sand Verbena