Characteristic features and economic importance of family Gramineae

  • This family is also known as Poaceae family.
  • The family consists of plants that are generally cultivated as crop plants for food.
  • They are terrestrial, annual herbs.
  • They are typically monocotyledonous.

Roots: They have fibrous or adventitious root system. Some may have stilt roots (e.g. maize).

Stem:

  • Stem is erect and herbaceous with distinct nodes and internodes.
  • May be branched (branching from the base, i.e. tillering) or unbranched.
  • It is cylindrical, ribbed, hollow and joined at the nodes.
  • Greenish yellow in color and is liable to fall easily.

Leaves:

  • Leaves are simple. They may be cauline, alternate, green and exstipulate.
  • Entire margin with parallel venation and acute apex.
  • Leaf base has a sheath and membranous ligule is present at the junction of leaf sheath and leaf blade.

Inflorescence:

  • Terminal panicle, spike or spikelets
  • Spikelet may be short stalked, consisting of a pair of glumes (e.g. barley).
  • Male spikelets in terminal panicled racemes called tassel and female in axillary spikes called cob or ear (e.g. maize).

Flower:

  • Bracteate, sessile, zygomorphic and may be bisexual (e.g. rice) or unisexual (e.g. maize).
  • It is incomplete and hypogynous. Flower lies in between superior and inferior palea.

Perianth:

  • It is represented by two broad, thick and fleshy lodicules.

Androecium:

  • Stamens are either 3 (e.g barley, maize, wheat) or 6 (e.g. rice) in number and are polyandrous.
  • Filament is long, anthers are bilobed and dorsifixed when young and versatile when mature.

Gynoecium:

  • Monocarpellary and the ovary is superior.
  • It is unilocular with a single basal ovule.
  • Style may be present (e.g rice) or absent (e.g. wheat, barley).
  • Stigma 2 and are feathery.

Fruit: Caryopsis

Floral diagram with floral formula (Oryza sativa or rice):

Some important plants of the family:

  • Oryza sativa (Rice)
  • Triticum aestivum (wheat)
  • Zea mays (maize)
  • Sorghum vulgare (broom corn)
  • Eleusine coracan (millet)
  • Sachharum officinarum (sugarcane)
  • Hordeum vulgare (barley)
  • Cymbopogan citramus (lemon grass)
  • Dendrocalamus strictus (bamboo)
  • Cynodon dactylon (dubo)

Economic importance:

  • Food: Oryza sativa, Zea mays, Triticum aestivum, Hordeum vulgare, Sorghum vulgare Eleusine coracana are used as food for mankind.
  • Zea mays, Cynodon, Poa, Saccharum are used as fodder.
  • Saccharum officinarum is the source of sugar.
  • Cymbopogan citratus gives reddish yellow oil with strong odour used in soaps and in medicine.
  • Dendracalamus strictus stem is used for making baskets, htus, mats, furniture etc.
  • Hordeum vulgaree barley water is used to expel stone from the kidney.
  • Citronella oil is used as external insecticide.
  • Andropogan odoratus yields ginger oil, which is used as digestive.
  • Poa, Agrostris, Cynodon are ornamental plants.

Characteristic features and economic importance of family Gramineae