TAXONOMY: GRAMINAE OR POACEAE FAMILY

· The Graminae family is also known as the Grass family.

· There are about 530 genera and 5200 species.

· They are widely distributed.

Some economically important members of the Poaceae family are:
· Triticum aestivum, WHEAT - Important cereal crop
· Oryza sativa, RICE - Important cereal crop
· Zea mays, Maize - Important cereal crop
· Cynodon dactylon, DUBO - important religious and medicinal plant
· Saccharum officinarum, SUGARCANE - Important for sugar
· Bambusa arundinacea. BAMBOO - Important medicinal and wood plant

1. Habit/habitat: Annual herbs or sometimes perennial shrubs, mesophytic, wild or cultivated.

2. Root: Fibrous root and branched or adventitious

3. Stem: Erect or prostrate, runner, aerial, herbaceous or woody, fistular or solid, cylindrical, glabrous or hairy, branched or unbranched.

4. Leaf: Exstipulate, sessile, simple, alternate, leaf is divided into two parts.

· The lower part is a thick leaf sheath, which covers the internode, and the upper part is a thin leaf blade.

· Its inner surface is glabrous and its outer is rough or hairy.

· At the base of the blade, there is a membranous colourless hairy structure called ligule and two sickle-shaped structures called auricle.

· Leaf-blade is long narrow, lanceolate, acute or acuminate, parallel venation.

5. Inflorescence: Spike or panicle of spikelet.

· Each spikelet consists of a sterile bract called glume.

· Each glume is boat-shaped with a thick mid nerve.

6. Flowers: Bracteate, sessile, incomplete, hermaphrodite, rarely unisexual, zygomorphic, hypogynous.

· Each flower consists of two covers the outer lemma and the inner palea.

· The lemma bears stiff threadlike outgrowth called awn.

· The lemma and palea enclose androecium and gynoecium.

7. Perianth: When calyx and corolla are not differentiated then it is called perianth.

· It is represented by two or three membranous lodicules.

8. Androecium: Stamens 3 or 6, polyandrous. Anther – dithecous, versatile

9. Gynoecium: Carpel – 1, monocarpellary, sometimes carpels – 3, tricarpellary, syncarpous.

· Ovary – superior, unilocular,

· Basal placentation.

· Stigma – feathery and bifid

10. Fruit: Caryopsis

11. Seed: Endospermic, monocotyledonous

Systematic Position

Class: Monocotyledonae
Series: Glumaceae
Family: Graminae

Diagnostic Characters of the Poaceae family are:
· Root - adventitious or fibrous.

· Stem - erect and cylindrical.

· Leaves - narrow, lanceolate, parallel venation and consisting of leaf sheath and leaf blade.

· Inflorescence - a spike of spikelets.

· Perianth is represented by 2 or 3 lodicules.

· Stamens – 3 or 6, polyandrous.

· Anther dithecous, versatile,

· Carpels – 1 or 3, syncarpous,

· Ovary superior,

· Basal placentation,

· Stigma feathery and bifid,

· Fruit caryopsis.

Common Plants of the Poaceae family are:
· Almost all cereal crops
· Triticum aestivum (Wheat)
· Oryza sativa (Rice)
· Zea mays (maize)
· Hordeum vulgre (Barley)
· Note: Hordeum is the oldest cultivated plant.
· Avena sativa
· Bambusa vulgaris (Bamboo)
· Dendrocalamus (Bamboo)
· Saccharum officinarum (sugar-cane)
· Cynodon dactylon (grass)
· Eleusine coracana

High Yielding Points from TAXONOMY

1. Shapes of corolla:
a. Cruciform: cross(x) like corolla eg. Cruciferae
b. Tubular: tube-like eg. sunflower
c. Papilionaceous: butterfly shape eg. legumes
d. Bilabiate: 2 lipped eg. libiatae
e. Personate (masked): bilabiate corolla with a narrow opening

2. Types of nomenclature:
a. Holotype: Specimen used by the author to confer scientific name to species
b. Isotype: Duplicate of holotype
c. Paratype: specimen cited with the original description other than holotype or isotype
d. Neotype: If the original specimen is lost it can be substituted by another specimen collected from the same locality
e. Lectotype: Specimen selected from the original material selected to serve as nomenclature type [@ HIPaNL]

3. Famous book ‘Species Plantarum’ was written by Carolus Linnaeus but ‘Genera Plantarum by Batham and Hooker

4. In the artificial system of classification, one or two characters are considered given by Carolus Linnaeus

5. In the natural system of classification, a large no. of traits are considered, given by Bantham and Hooker

6. Phylogenetic system of classification was given by A. Engler, Karl A. Prant and John Hutchinson.

Also, Read Notes of other Lessons of Botany:

TAXONOMY: GRAMINAE OR POACEAE FAMILY

High Yielding Points from TAXONOMY

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