Weed Seed - Japanese stiltgrass (Microstegium vimineum)

Invasive Plant - Japanese stiltgrass (Microstegium vimineum)

Family

Poaceae

Synonyms

Andropogon vimineum

Distribution in Canada

Not known to occur in Canada.

Duration of life cycle

Annual

Seed/Fruit type

Spikelet - grain enclosed by 2 pairs of bracts

Seed identification features

Size

  • length: 2.5–3.2 mm
  • width: 0.7 mm
  • awn length: unknown

Shape

  • in outline: spikelet is long oval with two stalks (pedicels) projecting from base

Surface texture

  • dull, roughened by numerous small hairs on surface

Colour

  • straw-yellow

Other structures

  • upper half of fertile spikelet has small teeth along edges
  • pedicels are cup-tipped, and have long hairs along edges
  • pedicels occasionally support sterile spikelets
  • long awn may be found at top of spikelet

Similar species

Yellow bluestem (Bothriochloa ischaemum)

  • not known to occur in Canada
  • similar to Japanese stiltgrass spikelet in teeth and pedicel hair patterns
  • spikelet is up to 1.0 mm longer than Japanese stiltgrass, shiny and hairless (Japanese stiltgrass is dull, with numerous hairs)

Photos

Photo - Japanese stiltgrass (Microstegium vimineum) spikelets and grain
Japanese stiltgrass (Microstegium vimineum) spikelets and grain
Photo - Japanese stiltgrass (Microstegium vimineum) grain (caryopsis)
Japanese stiltgrass (Microstegium vimineum) grain (caryopsis)
Photo - Japanese stiltgrass (Microstegium vimineum) spikelet
Japanese stiltgrass (Microstegium vimineum) spikelet

Similar species

Photo - Yellow bluestem (Bothriochloa ischaemum) spikelet
Similar species: Yellow bluestem (Bothriochloa ischaemum) spikelet
Photo - Yellow bluestem (Bothriochloa ischaemum) spikelets
Similar species: Yellow bluestem (Bothriochloa ischaemum) spikelets
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