Family Graminae (Poaceae) | Description in Semi-Technical Terms

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Graminae (Poaceae)Biology Notes | Botany
Family- Graminae (Poaceae) | General Description in Semi-Technical Terms
For: Science Class 11

The Graminae family is also known as grass family. There are about 530 genera and 5200 species. They are widely distributed, Some economically important members are:

Triticum aestivum, WHEAT – Important cereal crop
Oryza sativa, RICE – Important cereal crop
Zea mays, MAIZ – Important cereal crop
Cynodon dactylon, DUBO – important religious and medicinal plant
Saccharrum officinarum, SUGARCANE – Important for sugar
Bambusa arundinaceae. BAMBOO – Important medicinal and wood plant

Habit/habitat: Annual herbs or sometimes perennial shrubs, mesophytic, wild or cultivated.
Root: Fibrous root and branched or adventitious
Stem: Erect or prostrate, runner, aerial, herbaceous or woody, fistular or solid, cylindrical, glabrous or hairy, branched or unbranched.
Leaf: Exstipulate, sessile, simple, alternate, leaf is divided into two parts. Lower part is thick leaf sheath, which covers internode, and upper part is thin leaf blade. Its inner surface is glabrous and outer is rough or hairy. At the base of blade, there is a membranous colourless hairy structure called lugule and two sickle shaped structures called auricle. Leaf blade is long narrow, lanceolate, acute or accumunate, parallel venation.
Inflorescence: Spike or panical of spikelet. Each spikelet consists of sterile bract called glume. Each glume is boat shaped with thick mid nerve.
Flowers: Bracteate, sessile, incomplete, hermaphrodite, rarely unisexual, sygomorphic, hypogynous. Each flower consists fo two covers the outer lemma and inner palea. The lemma bears stiff thread like outgrowth called awn. The lemma and palea encloses androecium and gynoecium.
Perianth: When calyx and corolla is not differentiated then it is called perianth. It is represented by two or three membranous lodicules.
Androecium: Stamens 3 or 6, polyandrous. Anther – dithecus, versatile
Gynoecium: Carpel – 1, monocarpellary, sometimes carpels – 3, tricarpellary, syncarpous. Ovary – superior, unilocular, basal placentation. Stigma – feathery and bifid
Fruit: caryopsis
Seed: endospermic, monocotyledonous
Floral formula :

Floral formula of Poaceae

Floral diagram :

Floral diagram of Poaceae

Systematic position
Class: monocotyledonae
——-Series: Glumaceae
————Family: Graminae
—————–Diagnostic Charaters

Root – adventitious or fibrous. Stem – erect and cylindrical. Leaves – narrow, lanceolate, parallel venation and consisting of leaf sheath and leaf blade. Inflorescence – spike of spikelets. Perianth is represented by 2 or 3 lodicules. Stamens – 3 or 6, polyandrous. Anther dithecus, versatile, Carpels – 1 or 3, syancarpus, Ovary superior, basal plancentation, stigma feathery and bifid, fruit caryopsis.

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One Comment

  1. Gopal kumar yadav
    Posted February 24, 2017 at 11:10 am


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