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, 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