Grass Family

Purple Needle Grass © TCorelli

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)
Grass Family Characteristics © LAbrams and RFerris

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 and oaks are examples of plants at Edgewood that are wind pollinated
    • About 12% of flowering plants and most conifers are wind-pollinated (U.S. 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.

U.S. Forest Service. Wind and water pollination. Forest Service. United States Department of Agriculture.

Browse Some Edgewood Plants in this Family