Notes, Exercises, Videos, Tests and Things to Remember on Family-Gramineae
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It is commonly known as grass family.
New name: Poaceae
This is the largest family of monocotyledon which includes 620 genera and more than 10,000 species. The members are cosmopolitan in distribution. Many cereal plants are included in this family. Thus, this family is considered as the economically important family.
Annual, biennial or perennial herbs, rarely woody. Shrubs (Thysanolena maxima)or tree-like reaching up to the height of 30 or even more (Bambusa).
The adventitious root system, some grasses shows moniliform roots whereas in Zea mays stilt roots are present.
Aerial, erect or prostrate, simple, sometimes branched near the base, solid and swollen node, fistular internode, cylindrical, glabrous, sometimes glaucous.
Cauline and ramal, ex-stipulate, sessile, simple, alternate, ligulate, leaf consists of leaf sheath and leaf blade with auricles and ligule. Leaf sheath partially or completely covers the internode. At the junction of leaf sheath and leaf blade, thin membranous ligule is present. A pair of pointed claw-like appendages known as auricles occur on either side of ligule, leaf blade is thin, flattened, narrow, linear to lanceolate with parallel venation.
Spike or panicle of spikelet. The inflorescence consists of many spikelets attached to the main axis known as rachis. Each spikelet consists of one to many florets attached to the central axis known as rachilla. A pair of sterile glumes occurs at the base of spikelet.
Bracteate, bracts are represented by outer lemma and inner pulea, sessile complete, rarely incomplete, bisexual, rarely unisexual(Zea mays), zygomorphic, trimerous hypogynous.
Sepals modified into 2 or 3 lodicules, sometimes absent(Bambusa).
Stamens 3 polyandrous, sometimes 6 (Oryzae, Bambusa), 2 (Sporobolus), 1(Uniola), anthers dithecous, versatile, sometimes dorsifixed, extrorse, inferior.
Carpel 1, monocarpellary, sometimes 2 or 3 bi or tri carpellary, syncarpous, ovary superior, unilocular with single ovule in basal placentation, style 2, sometimes 3 (Bambusa) or 1(Nardus), stigma two lateral feathery.
Br. % Plodicules A3 or 1-6 G1 or (2)