Poaceae (Gramineae)

About Poaceae or Gramineae

Systematic Position

Class -Monocotyledonae

Series-Glumaceae

Family-Gramineae or Poaceae

It is economically the most important family of monocotyledonous plants. It is also one of the largest families comprising about 6000 species and 620 genera of which about 900 species are present in India.

Vegetative characters : Plants are generally annual herbs, although some may be perennials and shrubs, rarely trees such as bamboo; stem, cylindrical, with clear nodes and hollow internodes, and underground rhizome as in perennial grasses; leaves; simple, arranged alternately, venation parallel.

Distinguishing features :

(1) Inflorescence spike of spikelet (Triticum), panicle of spikelets (Avena), spadix of spikelets (Zea)

(2) Flowers small, sessile, surrounded by two scales, lemma (inferior or outer palea) and palea (superior or inner palea). The lemma bear a long, stiff process called awn.

(3) Flowers zygomorphic, incomplete, hypogynous.

(4) Perianth generally represented by two lodicules, 3 in Bambusa, no lodicule in Anthoxanthum.

(5) Androecium 3 or 6, polyandrous, dithecous, introrse, versatile fixation of anthers.

(6) Tricarpellary, superior, unilocular ovary with basal placentation, stigma feathery.

(7) Fruit is caryopsis or nut (Dendrocalamus) or berry (Bambusa).

F.F. P2 or 3 (lodicules) A3 or 6

Economic Importance

The staple food grains (wheat, rice, jau, jowar, oat and bajra) for majority of the human population are obtained from this family. Fodder is provided by many grasses. Gur and sugar from sugarcane. We get medicine from Cymbopogon flexviosus. Several grasses produce volatile scented oil used in perfumery, e.g. khuskhus (Vetiveria zizanoides) and lemon grass. Some grasses including bamboo are used to produce paper.

Important Plants :

(1) Avena sativa (Oat, Jai)

(2) Triticum aestivum (Wheat)

(3) Sorghum vulgare (Jowar)

(4) Pennisetum typhoides (Bajra, Pearl millet)

(5) Hordeum vulgare (Jau, Barley)

(6) Saccharum officinalis (Sugarcane)

(7) Zea mays (Maize)

(8) Oryza sativa (Rice)

(9) Bambusa tulda (Bamboo)

(10) Cynodon dactylon (Doob grass)

(11) Erianthus arundinaceus (Sarkanda)

(12) Eleucine coracana (Ragi)

(13) Secale cereale (Rye)

(14) Dendrocalamus strictus (Solid bamboo)

(15) Vetivera zizanoides (Khus-khus)

(16) Cymbopogon citratus (Lemon grass)

(17) Cymbopogon nadrus (Citronella grass)

(18) Cymbopogon martinii (Ginger grass)