Graminae (Poaceae) - General Description in Semi-Technical Terms

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 diagram :

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.