Grass Family (Poaceae): Characters, Agricultural Value and Distribution Pattern

Diagnostic characters of Poaceae:

1. Habit: Annual or perennial (means lasting for an infinite period) herbs; rarely trees (bamboos).

2. Roots: Fibrous adventitious roots are seen in the Poaceae plant family members.

3. Stem: Herbaceous; cylindrical (looks like oval cross-section); jointed, hollow at internodes. In some rare cases, members of the family Poaceae forms a rhizome or a runner.

4. Leaves: Sessile with long sheathing base (sheath-like structure); alternate; simple; ligulate; parallel venation.

5. Inflorescence: Spike of spikelets or panicles of spikelets e.g., Dracaena indivisa. Each spikelet of Poaceae plants family member is composed of 2 - 5 flowers.

 It is enclosed by a pair of bracts that are generally known as glumes.

(a) Spike of spikelets: In this type of inflorescence, the spikelets form dense clusters in a sessile manner on the main axis, as in wheat.

(b) Panicles of spikelets: In this type of inflorescence, the spikelets are arranged on a branched axis-panicle as in oat.

6. Flower: Pedicillate (having pedicle or stalk in context of flower); bracteate, two bracts, palea and lemma enclose flower or floret; lemma contain bristle like awns, zygomorphic, incomplete; unisexual or hermaphrodite; hypogynous.

7. Perianth: In family Poaceae, the perianth is represented by two or three scale like lodicules.

8. Androecium: 3 stamens, sometimes 1,2 or 6; polyandrous; anther versatile.

9. Gynoecium: Monocarpillary; unilocular; ovary superior; stigma usually 2; feathery; type of placentation is basal generally observed in Poaceae family.

10. Fruits: Caryopsis.

11. Seed: Endospermic.

Floral formula of Poaceae:

Floral diagram of Poaceae:

Economic Importance of Poaceae:

The Poaceae family has greater importance than all other families of the flowering plants. It has importance for living beings as both for human and animals.

1. Food: All the cereals and millets belong to Poaceae angiospermic family. These are from the basic food of mankind. These plants are: i- Tirticum sp. (Wheat), ii- Avena sativa (oat 5), iii- Zea mays (corn), iv- Oryza sativa (rice), v- Hordeum vulgare (barley ), vi- Scalecereale (rye), vii- Penisetum typhoideum Sorghum vulgare.

2. Fodders: Most of the fodders of the animals also belong to the Poaceae angiospermic family. The dried stems and leaves of the cereal crops are used as fodder for the cattle.

3. Sugar: Saccharum officinarum is a member of Poaceae angiospermic family and it's generally known as sugar cane. And sugar is obtained from the juice of Saccharum officinarum (sugar cane). 

4. Ornamental plants: Many plants are cultivated in gardens, parks, and in houses for their scented and ornamental purposes to boost up the beauty of nature i.e. grasses are used in lawns, e.g. Agrostis, Poa, Festuca etc. So these plants have ornamental significance commercially and locally.

5. Use of Bamboo: Bambusa (bamboo) taken from members of family poaceae are used as a building material. These are used for thatching huts, making boats, carts, pipes etc. Their split stems are woven into mats, fans, hats, and of course umbrella. Their leaves are given to horses for curing cough (used for the treatment of cough).

6. Aromatic oils: Certain grasses give aromatic oil, e.g. Cymbopogon citratus ( generally known as lemon grass). It gives lemon grass oil. This oil is used in perfumes and soap industry for making infusions.

7. Paper industry: Some species of Poaceae grass family are used for making paper.

8. Alcohol and beverages: Ethyl alcohol and many other beverages are prepared from cereals. For example: 

i- wine is prepared from rye, ii- corn, and rum molasses from sugar cane.

9. Ropes: Fibers are taken from the leaves of Saccharum munja. These fibers are used for the development of ropes.

Distribution pattern of Poaceae:

The Angiospermic Poaceae Plants family is distributed throughout the world. It has about 600 genera and 10,000 species. There are 158 genera and 492 species of this family that have been discovered in South Asia.

Common species of Poaceae:

• Triticum vulgare, commonly known as wheat.
• Zea mays, commonly known as corn.
• Avena sativa, commonly known as oat.
• Oryza sativa, generally known as rice.
• Bambusa, commonly known as bamboo.
• Saccharum officinarum, commonly known as Sugar cane.