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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.
Diagnostic Characters
1. Mostly annual herbs with fistular stem
2. Leaves distichous with sheathing bases and ligule
3. Inflorescence unit is a spikelet
4. Perianth is reduced to lodicules or even absent
5. Anthers are versatile
6. Stigma are feathery
7. Fruit is caryopsis
Common plants
Alloteropsis cimicina Bambusa bambos
Coix lacryma - jobi
Eleusene coracana Oplismenus burmanii
Oryza sativa Pennisetum polystachyon
Rottboellia exatlata Saccharum officinale
Habit : 1.mostly annual (Oryza) or perennial
(Sacharum) herbs
Roots :Fibrous and mainly plant possess rhizomes
Stem :1.Stem of grasses is called a culm
2.It is usually fistula or hollow
3.The stem is erect ,prostrate or creeping
Leaves: Simple
Alternate
Parallel venation
Exstipulate : stipule absent
Distichous
Ligulate : Preventing water or insect from
penetrating in to the sheath.
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
Flowers : Small
Bracteates
Bracteolate (Lemma & Palea)
Sessile
Usually Bisexual (Oryza ) ,Rarely Unisexual (Zea)
Hypogynous
Zygomorphic
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.
Gynoecium : Bi 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 Bambusa .
Stigmas are 2 and feathery
Fruit : A caryopsis ( fruit wall is completely
fused with the seed coat)
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
Plants of economic importants
 Food: this family consists of the most important
food plants called cereals
 Wheat (Triticum aestivum)
 Rice (Oryza sativa )
 Maize (zea mays)
 Barley (Hordeum vulgare)
 Oats (Avena sativa)
 Ragi (Eleusine coracana)
 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 : Cynodon (Bermuda grass) , Agrostis
(florin grass) , Poa (meadow grass) and Festuca
(festuca grass) are grown in lawns.
Gramineae (poaceae).it is the one of the largest plant family