Grass Family

Poaceae (poh-AY-see-ee)

Iconic Features

• Hollow stems
• Usually narrow, sheathing leaves
• Small, petalless, pale flowers
• Fruit a grain

Description (Jepson)

• Monocotyledons (monocots) – monocots are a major lineage of flowering, mostly herbaceous plants, generally characterized by
  • Single seed leaf (cotyledon)
  • Linear or oblong leaves with parallel venation
  • Flower parts in threes
  • Pollen grains with a single pore
  • Vascular bundles scattered in stem
  • Fibrous root system
• Annuals or herbaceous perennials
• Leaves
  • Usually narrow leaves sheathing the stem
  • Sheaths usually with a small appendage called a ligule
  • Alternate (1 leaf at each junction with stem)
• Flowers
  • Small, generally bisexual, petalless flowers in spikelets
  • Wind pollinated
• Fruit a grain (a dry, one-seeded fruit with a fused seed coat)

Notes

• Approximately 10,550 species worldwide
  • Includes wild and cultivated species of wheat, rice, corn, rye, fescue, brome, oats, barley, and bamboo
  • Greatest economic importance of any plant family
• Grasses, oaks, and silk tassels are examples of plants at Edgewood that are wind pollinated
  • About 12% of flowering plants and most conifers are wind-pollinated (US Forest Service)
  • These plants do not waste energy on flower features that attract animal pollinators; instead, their flowers generally have these characteristics
    • Minute, inconspicuous, petalless flowers
    • No nectar
    • Stamen (male flower part) and stigma (pollen-receiving part of the pistil/female structure) are exposed to air currents
    • Male flowers produce a great deal of pollen, which is very small, dry, and easily airborne, as all allergy sufferers know!
• Scientific name from the included genus Poa, from the Greek for “fodder”
• Represented by 57 species at Edgewood

See General References

Specific References

Abrams, L.R. and R.S. Ferris. 1940-1960. Illustrations. Illustrated Flora of the Pacific States, Washington, Oregon and California (IFPS). Four volumes. Stanford University Press, Stanford, California. Public Domain.

US Forest Service. Celebrating Flowers: Wind and Water Pollination. United States Department of Agriculture.

Browse Some Edgewood Plants in this Family