Gramineae (poaceae).it is the one of the largest plant family

poaceae or true grass is a monocotyledon family.the family consist mainly grasses.different varieties of grasses are present under the categories.one of the most advanced reproductive mechanisms are present in the family.

1. GRAMINEAE ( POACEAE ) Class : Monocotyledons Series : Glumaceae Family : Poaceae 668 genera, 9500 species ( 1997 ) The family is cosmopolitan in distribution

2. Etymology The Poaceae name was given by John Hendley Barnhart in 1895 , based on the tribe Poeae ( described in 1814 by Robert Brown ), and the type genus Poa (described in 1753 by Linnaeus ). The term is derived from the Ancient Greek term for grass .

3. Diagnostic Characters Mostly annual herbs with fistular stem Leaves distichous with sheathing bases and ligule Inflorescence unit is a spikelet Perianth is reduced to lodicules or even absent Anthers are versatile Stigma are feathery Fruit is caryopsis

4. Common plants Alloteropsis cimicina Bambusa bambos

5. Coix lacryma - jobi

6. Eleusene coracana Oplismenus burmanii

7. Oryza sativa Pennisetum polystachyon

8. Rottboellia exatlata Saccharum officinale

9. Habit : 1. mostly annual ( Oryza ) or perennial ( Sacharum ) herbs

10. Roots : F ibrous and mainly plant possess rhizomes

11. Stem : 1. Stem of grasses is called a culm 2. I t is usually fistula or hollow 3. T he stem is erect ,prostrate or creeping

12. Leaves : Simple Alternate Parallel venation Exstipulate : stipule absent Distichous Ligulate : Preventing water or insect from penetrating in to the sheath.

13. Inflorescence Flowers of poaceae are characteristically arranged in spikelets . Each spikelet has a very short or minute axis called Rachilla Spikelet having one or more florets A spikelets consist 2 bracts at the base Glumes and followed by one or more florets A floret consist of the flower surrounded by 2 bracts one external lemma & one internal palea Perianth is absent or reduced to scales ----- lodicules

14. Flowers : Small Bracteates Bracteolate ( Lemma & Palea ) Sessile Usually Bisexual ( Oryza ) ,Rarely Unisexual ( Zea ) Hypogynous Zygomorphic

15. Androecium : stamens are usually 3 and belong to outer whorl. The inner whorl of stamens is generally completely absent . Anthers are dithecous , versatile and introse &which open by a longitudinal slit . The stamens are 6 , arranged in 2 whorls of 3 each in Bambusa and Oryza The stamens are numerous in Pariana .

16. Gynoecium : B i or tricarpellary and syncarpous or monocarpellary & superior . It is always unilocular with a single ovule on basal placentation Styles usually 2 (rarely 1 or 3 0r absent) and 3 in B ambusa . Stigmas are 2 and feathery

17. Fruit : A caryopsis ( fruit wall is completely fused with the seed coat)

18. Advanced characters Herbaceous , annual or perennial habit Exstipulate leaves with sheathing bases and ligules Flowers arranged in distinct inflorescence called spikelet Highly reduced , inconspicuous and zygomorphic flowers Perianth is represented by lodicules Reduction in the number of stamens to three Monocarpellary and unilocular ovary with a single ovule on basal placenta Fruit is a caryopsis

19. Plants of economic importants Food: this family consists of the most important food plants called cereals Wheat ( Triticum aestivum ) Rice ( O ryza sativa ) Maize ( zea mays ) Barley ( Hordeum vulgare ) Oats ( Avena sativa ) Ragi ( Eleusine coracana )

20. Paper : Bambusa and dendrocalamus yield bamboos .Paper pulp is made out of bamboos Medicinal : Roots of Vetiveria zizanioides are medicinal and give a pleasant scent Valuable perfumery oils are obtained from Cymbopogon citratus ( lemon grass) and Andropogon odonatus ( ginger grass) Ornamental : C ynodon (Bermuda grass) , Agrostis (florin grass) , P oa (meadow grass) and Festuca ( festuca grass) are grown in lawns.

21. Thank you