Weed Seed: Corn gromwell/Field gromwell (Buglossoides arvensis)

Family

Boraginaceae

Synonyms

Lithospermum arvense

Distribution in Canada

Found in BC, MB, ON, QC, NS

Duration of life cycle

Annual

Seed/Fruit type

  • nutlet - a one-seeded, dry fruit with a thick shell
  • nutlets develop in groups of 4

Seed identification features

Size

  • length: 2.5–3.0 mm
  • width: 1.5 mm

Shape

  • in outline: egg-shaped
  • in cross-section: rounded triangular

Surface texture

  • shiny with scattered warts and pits
  • raised ridge on inner side

Colour

  • grey to grey-brown
  • brown base and surface pits

Other structures

  • rounded base is a distinguishing feature
  • base is dull, brown, with 2 raised warts

Similar species

Blueweed (Echium vulgare)

  • found across Canada and the United States
  • similar to corn gromwell in size, triangular shape and brown colour
  • strongly angled nutlets, with raised rim around base

Gromwell (Lithospermum officinale)

  • found in MB, ON, QC, NB, and the north-eastern United States
  • similar to corn gromwell in size, shape, and rounded, brown base
  • nutlets are more rounded and a whitish colour

Photos

Photo - Corn gromwell (Buglossoides arvensis) seed (front view, showing ridge)
Corn gromwell (Buglossoides arvensis) seed (front view, showing ridge)
Photo - Corn gromwell (Buglossoides arvensis) seed (side view, showing seed shape)
Corn gromwell (Buglossoides arvensis) seed (side view, showing seed shape)
Photo - Corn gromwell (Buglossoides arvensis) seeds
Corn gromwell (Buglossoides arvensis) seeds

Similar species

Photo - Similar species: Blueweed (Echium vulgare) nutlet
Similar species: Blueweed (Echium vulgare) nutlet
Photo - Similar species: Gromwell (Lithospermum officinale) nutlet
Similar species: Gromwell (Lithospermum officinale) nutlet
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