FAMILY POACEAE

Family: Poaceae or Gramineae (Grass family)

Distribution: cosmopolitan in distribution, mostly found in temperate region. This family consists of 668 genera and 10,000 species

Habitat: terrestrial, mesophyte or aquatic (Oryza sativa), wild or cultivate for cereals

Habit: annual or perennial herbs, shrubs or trees like (Bambusa)

Roots: adventitious root, fibrous root

Stem: aerial, erect or prostrate, creepers (Cynodon), branched or unbranched (Zea mays), cylindrical, herbaceous or woody (Bambusa), solid (Zea mays) or fistular (Tritucum aestivum), glabrous, distinct nodes and internodes, internodes are surrounded by leaf sheath

Leaf: cauline and ramal, alternate ex-stipulate, sessile simple, lanceolate, entire acute apex, glabrous, unicoasted parallel venation, leaf is differentiating into leaf lamina and leaf sheath, at the junction between leaf sheath and leaf lamina presence of small membranous structure called ligule

Inflorescence: racemose, spike of spikelets (Triticum aestivum), panicle (Oryza sativa)

Flower: bracteate, represents by glumes, bracteolate represented by palea and lemma with awn, sessile, zygomorphic, incomplete or complete, bisexual or unisexual (Zea mays), trimerous hypogynous

Perianth: tepals absent, or represented by two or rarely three (Bambusa) or many (Ochlandra) membranous scale called lodicules, inferior

Androecium: stamens usually three or reduce to two or one, rarely six (Oryza, Bambusa), polyandrous, anther dithecous, versatile, filament thin, inferior

Gynoecium: carpel one or three, monocarpellary or tricarpellary, syncarpous, ovary superior, unilocular with single ovule, basal placentation, style short, stigma plumose

Fruit: simple, dry, caryopsis Seed: one cotyledon, albuminous

Floral diagram with 

Floral formula

 

Identifying characters

Presence of distinct nodes and internodes, internodes are covered by leaf sheath

Leaf is differentiating into leaf sheath and leaf lamina

Presence of leaf legule

Inflorescence is spike of spikelets, panicle

Presence of lemma and palea, lemma has awn

Trimerous, incomplete flower

Perianth represented by lodicules

Versatile stamens

Mono or tricarpillary, basal placentation, plumose stigma

Fruit is caryopsis

 

 

Classification

Kingdom: Plantae

Division: Phanerogams

Sub-division: Angiospermae

Class: Monocotyledonae

Series: Glumiflorae

Order: Graminales

Family: Poaceae (Gramineae)  

Economically important plants

Oryza sativa

Zea mays

Triticum aestivum

Cynodon dectylon

Eleusine corocana

Hordeum vulgare

Bambusa arundinaria

Saccharum officinarum