Family Poaceae

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The grass family

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 Poaceae Family (GRAMINEAE):

  Poaceae Family ( GRAMINEAE) Grass Family (Monocot)

Distribution:

Distribution This family is distributed throughout the world. It has  600  genera and  10,000  species. There are  158  genera and  492  species of this family in Pakistan.

Description:

Description Habit:  Annual or perennial herbs; rarely tree ( bamboos). Roots:  Fibrous adventitious . Stem:  Herbaceous; cylindrical; jointed, hollow at internodes . Sometimes, forms rhizome or runner. Leaves:  Sessile with long sheathing base; alternate; simple; ligulate ; parallel venation .

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Inflorescence : Spike of spikelets or panicles of spiklets .  Each spiklet is composed of 2-5 flowers. It is enclosed by a pair of bracts called  glumes. Spike of spikelets :  The spiklets form dense clusters in sessile manner on main axis as in wheat. Panicles of spikelets :  The spiklets are arranged on a branched axis-panicle as in oat . Each spikelet contains three florets, two in periphery fertile & inner sterile.

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Flower:  Sessile or pedicellate ; bracteate , two bracts  palea   and  lemma  e nclose flower or floret; lemma contain bristle like  awns, zygomorphic ; incomplete ; hermaphrodite; hypogynous . Perianth :  Represented by two or three scale like  lodicules .

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Androecium :  3 stamens, sometimes 1,2 or 6; polyandrous; anther  versatile. Gynoecium : Monocarpillary ; unilocular ; ovary superior; stigma usually 2; feathery; basal placentation . Fruits: Caryopsis Seed:  Endospermic .

Floral Formula & Diagram:

Floral Formula & Diagram

Economic Importance:

Economic Importance This family has greater importance than all other families of the flowering plants. It has importance both for man and animals. Food : All the cereals and millets belong to this family. These from the basic food of mankind. These plants are: Tirticum sp (Wheat). Avena sativa (oat).   Zea mays (corn). Oryza saliva (rice). Hordeum vulgare ( barley), Scale cereale (rye). Fodders : Most of the fodders of the animals also belong to this family. The dried stems and leaves of the cereal crops are used as fodder for the cattle .

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Ornamental plants : Many grasses have ornamental significance e.g. Boa, Festuca etc . Paper industry:  Some species of grasses are used for making papers. Alcohol and beverages:  Ethyl alcohol and many other beverages are prepared form cereals. For example, wine is prepared from rye, corn and rum molasses form sugar cane .

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Bamboo : Bambusa (bamboo) are used as building material. These are used for thatching huts, making boats, carts pipes etc. Their spilt stems are woven into mars, fans, hats and ‘course umbrella. Their leaves are given to horse for curing cough and cold . Sugar : Sugar is obtained from the juice of Saccharum officinarum (sugar cane).

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