POACEAE - GRASS FAMILY
Scientific Description:
Annual, biennial or perennial herbs, rarely 'woody' (Bamboos: Subfamily Bambusoideae), often rhizomatous or stoloniferous. Flowering stems usually cylindrical, with solid nodes and hollow internodes, rarely solid throughout. Phyllotaxis 1/2. Leaves consisting of sheath, ligule and lamina (blade). Sheaths surrounding stem, with overlapping free or connate margins, sometimes with 2 small auricles at mouth. Ligule situated at junction of sheath and blade, either membranous or a fringe of hairs, rarely absent. Blades usually linear or filiform, often setaceous, rarely lanceolate to ovate, usually sessile and contracted at junction with sheath, rarely with a false petiole, usually with ± prominent parallel veins. Leaf epidermis with long and short cells, some of the latter usually containing silica bodies, others with corky walls. Hairs of 2 kinds often present: macro-hairs (1-celled, stout, thick-walled, visible to naked eye) and micro-hairs (microscopic, normally 2-celled, slender or globose, distal cell thin-walled). Inflorescence various, composed of florets aggregated in spikelets arranged in spikes, racemes, panicles or false racemes in which a sessile spikelet is accompanied by 1−2 pedicellate ones or their rudiments; inflorescence rarely reduced to a single spikelet. Flowers usually hermaphrodite, rarely unisexual; ovary, styles and stamens enclosed between 2 bract-like structures, the whole forming a floret; florets 1−many, inserted alternately on 2 sides of a slender, jointed axis (rachilla) subtended by bracts (glumes), the whole comprising a spikelet. Glumes (0−)l or 2(−3), lower one sometimes suppressed or absent. Lower bract of floret (lemma) often awned and with a thickened base (callus). Upper bract (palea) usually membranous and 2-keeled, sometimes reduced or absent. Stamens l−3(−6) (in Turkish genera), subtended by (0−)2(−3) small hyaline scales (lodicules) and normally consisting of long, delicate filaments and 2-locular anthers dehiscing by longitudinal slits (rarely by pores). Ovary superior, 1-locular; styles usually 2; ovule 1, attached on adaxial side of loculus to a point or line visible in fruit as the hilum. Fruit a caryopsis, rarely with free, mucilaginous pericarp.
Reference:
Davis PH (1985). Poaceae, In: Davis PH (ed.), Flora of Turkey and the East Aegean Islands, Edinburgh University Press, Edinburgh, 9: 158−159.
Public Description:
The “grass family” grows almost everywhere in all continents, except for the highest altitudes and polar regions, in freshwater and marine habitats. Plant communities dominated by grasses account for about 24% of the earth’s vegetation.They do not usually have a true flower structure, they are characterized by striped leaves and spike-growing fruit structures.Members of the grass family is the most important food source consumed as food on the world.They are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, barley, and millet as well as forage, building materials (bamboo, thatch, straw) and fuel (ethanol).
References:
Anonymous 1 (2016). https://en.wikipedia.org/wiki/Poaceae#Distribution/,Accessed date: 03.03.2016.
Anonymous 2 (2016). http://global.britannica.com/plant/Poaceae/,Accessed date: 03.03.2016.
