Order Graminales, Family- Gramineae | The Monocotyledones

The below mentioned article provides an overview on Order Graminales, Family- Gramineae. After reading this article you will learn about: 1. Introduction to Order – Graminales 2. Characteristic Features of Order – Graminales 3. Explanation 4. Economic Importance.

Introduction to Order – Graminales:

According to Hutchinson this is the 111th order (the last one) of the phylum Angiospermae, subphylum Monocotyledones and division Glumiflorae. He has considered this order to be highest evolved among the phylum Angiospermae. This order comprises of a single family the Gramineae. The family has been described here in detail.

Bentham and Hooker have also considered the Gramineae to be highest evolved among Phanerogams. They have placed the Gramineae along with four other families including Cyperaceae in their seventh series – the Glumaceae of class Monocotyledones. Engler and Prantl have placed the Gramineae along with the Cyperaceae in the fourth order- the Glumiflorae of Monocotyledoneae.

Flower subtended by 2 bracts (lemma and palea); perianth usually represented by lodicules; fruit a caryopsis, rarely a nut, berry, or utricle; stems mostly hollow between the nodes.

Characteristic Features of Order – Graminales:

World-wide in distribution; annual or perennial herbs, rarely shrubs or trees, stems erect, ascending or prostrate creeping, usually branched at the base in perennials forming sterile shoots (innovations) and flowering stems (culms), in annuals only the culms present; culms cylindrical rarely flat jointed.

Usually hollow in the internodes, solid at the nodes; leaves solitary at nodes, sometimes crowded at the base of the stems, alternate, two rowed, consisting of sheath, ligule and blade; sheath encircles the culm, margins of sheath free and overlapping and more or less connate, swollen at the base; ligule situated at the junction of sheath and blade, membranous or reduced to fringe of hairs, rarely absent; blades long, narrow, rarely broad, passing gradually into the sheath, rarely with a petiole like base, flat, convolute or terete, parallel venation; flowers generally hermaphrodite, rarely unisexual, small and inconspicuous, perianth represented by 2 or 3 minute hyaline or, fleshy scales known as lodicules, sub-sessile between two bracts, i.e., lemma and palea, the whole structure known as floret or a false flower; florets one to many, distichous, sessile on a short slender axis, the rachilla and bearing at the base two empty bracts, the upper and lower glumes, the florets and glumes forming a spikelet; spikelet’s pedicel-led on open or contracted panicles or racemes, or sessile in spikes; stamens 1 to 6, rarely more, usually three, hypogynous, filaments delicate, anthers bicelled, versatile, dehiscing by longitudinal slit; ovary unilocular, with one anatropous ovule, often adnate to the adaxial side of the carpel; styles usually two, rarely 1 or 3; stigmas 2, feathery (plumose); fruit caryopsis, with a thin pericarp adnate to the seed, rarely a nut or berry; seeds endospermic, embryo small.

Explanation on Family—Gramineae (Poaceae):

There are about 500 genera and 4,500 species in this family (Willis).

Distribution:

The members (grasses, cereals and millets, etc.) belonging to this family are cosmopolitan in distribution. The plants are commonly distributed in temperate regions, but they are also not uncommon in tropical and sub-tropical aleas.

In our country the family is represented by many food crops, e.g., Triticum aestivum (Wheat), Oryza sativa (Rice), Hordeum vulgare (Barley), Zea mays (Maize), Sorghum vulgare (Millet Jowar), Avena saliva (Oat), Saccharum officinarum (Sugarcane), etc. The grasses, e.g., Poa, Festuca, Andropogon, Cynodon, Cymbopogon, etc., and bamboos are very common.

The great adaptability of the different species has enabled them to survive under the most varied conditions, some are aquatic while some are xerophytic and found on sea-shores and in arid regions.

Habit:

Mostly the plants are annual, biennial or perennial herbs or shrubs. The largest woody species are the bamboos, which may grow to more than 100 feet in height and several inches in diameter. Most of the plants, e.g., grasses, are wild while some are cultivated for valuable food.

Root:

Generally adventitious, fibrous, fascicled, stilt (e.g., Zea mays, Sorghum vulgare, etc.).

Stem:

The stem may be erect, prostrate or even creeping. Usually fistular (hollow), rarely solid (e.g., Zea, Saccharum, etc.). The internodes are long and nodes are conspicuous. In many grasses the runners and suckers are also developed. Among the perennial grasses, usually the rhizomes and root stocks are formed, which help in vegetative propagation. Small tubers and corms are also found in so many species.

In this family the aerial stem is commonly known as ‘culm’ which is usually terete (cylindrical) but in few cases flattened.

In most grasses the main axis only develops lateral branches from the basal buds. These branches are ’tillers’.

Leaves:

In most of the members of this family, the foliage leaf can easily be divided into two parts, the sheath and the blade (lamina).

The leaf sheath usually covers the internode completely or partially. The inner surface of leaf sheath is usually glabrous (smooth) while the upper surface is variously grooved and either glabrous or hairy.

At the junction of the leaf sheath and leaf blade there occurs a thin membranous outgrowth, the ligule. In some species the ligule is represented by only few hairs.

In many species there are two lateral pointed outgrowths above the ligule are known as auricles. They are well developed in Hordeum and Oryza.

The leaf blade is long, narrow, acuminate and with parallel venation.

The leaves are usually sessile very rarely petiolate (e.g., in Panicum sagittaefolium), alternate, lanceolate, entire or hairy margins, surface smooth or glabrous.

Inflorescence:

The inflorescence is somewhat complex in this family. The inflorescence is composed of several to many spikelets, which are combind in various manners on a main axis called the rachis. Some are in compound spikes (e.g., in wheat), others are in racemes (e.g., in Festuca), while some are in panicles (e.g., in Avena). Each spikelet may bear one to several florets (flowers) attached to a central stalk known as rachilla.

The usual structure of spikelet is as follows:

There is a pair of sterile glumes at the base of spikelet, the lower, outer glume called the first, and the upper, inner one called the second. Just above the glumes, there is series of florets, partly enclosed by them. Each floret has at its base a lemma and palea.

The lemma is the lower, outer bract of the floret. Usually the lemma also known as inferior palea bears a long awn as an extension of the midrib at the apex or back. The floral parts borne in the axil of lemma.

The palea (also known as superior palea), often with two longitudinal ridges (keels or nerves), stands between the lemma and the rachilla. The pressence of two nerves in palea makes some people to conclude that it is formed by the fusion of two bracteoles. The essential organs of the flower are protected in between lemma and palea. Many species have other florets on the rachilla, the upper or lower of some being sterile.

Flower:

Sessile, bracteate (the bracts are represented by lemma and palea), hermaphrodite or unisexual, zygomorphic, hypogynous, irregular.

Perianth:

Sometimes absent or represented by two or rarely three (Bambusa) minute, membranous scale like lodicules (here the perianth leaves are known as lodicules).

Androecium:

Usually three stamens, sometimes six, e.g., in Oryza, Bambusa, etc., and sometimes reduced to two or one, the stamens are with free, long slender filaments and versatile anthers. Anthers two-celled, dehisce longitudinally.

Gynoecium:

One carpel (monocarpellary) (though the pistil is tricarpellary but only one carpel is functional, syncarpous); unilocular ovary, superior, single ovuled (anatropous ovule); style short, usually two, stigma usually two arise from the carpellary wall, feathery. In maize the style is long and silky; placentation basal.

Fruit:

Usually caryopsis (pericarp completely united with the seed coat), rarely a nut or berry (e.g., in Bambusa). In Dendrocalamus it is a nut.

Seeds:

Endospermic (albuminous).

Pollination:

Usually anemophilous (wind pollination), cross pollination, may also take place.

1. Triticum aestivnm (Verna.-Gehun):

Habit:

The wheat plant is an annual cereal. In India all wheats are winter grown, except in Nilgiri and Palini hills where two crops (winter and summer) are taken.

Root:

Adventitious, fibrous.

Stem:

The stem is 3 to 4 feet in height or more. The stem (culm) is erect, cylindrical sometimes furrowed, and either glabrous or scabrous. The nodes are 5 to 7 in number, the average number is six. Each node is swollen and solid. The internode s are generally hollow. The lower and upper internodes are covered by the leaf-sheaths. Branching by tillers.

Leaves:

The normal leaf of wheat is divisible into two parts, the leaf-sheath and the leaf blade (lamina). The leaf also possesses two accessory organs, the ligule and the auricle.

The sheath is inserted on the node and envelops the stem. The leaf sheath is usually thicker than the leaf blade with thin transparent margins. The surface is either glabrous or hairy.

The leaf blade is long, narrow, lanceolate, acuminate with parallel venation, sometimes hair also present along the veins.

At the junction of leaf blade and leaf sheath thin membranous ligule encircles the stem. It is colourless and hairy.

Two claw-like appendages near the ligule region are prominent, these are known as auricles. They are usually hairy and pale green.

Inflorescence:

Spike of spikelets. This is a compound spike bearing two rows of lateral spikelets on its axis and a single terminal spikelet. There are many short internodes on the main axis. Each internode is narrow at the base and broader at the apex. One side of internode is convex while the other side is concave or flattened.

The position of concave side alternates with convex side and the whole axis has a zig zag appearance. The spikelets are sessile and arranged alternately, the spikelet is inserted on the apex of the internode.

Spikelets:

The solitary and sessile flowers (florets) are arranged on a short, jointed axis, the rachilla. The flowers are alternately placed on the spikelet. At the base of each spikelet, two glumes occur. They appear to be opposite of each other. Actually one glume overlaps the other.

The normal glume is somewhat boat shaped, with a thick main nerve, dividing it into two unequal halves. The base of the glume is rounded while sometimes the nerve extends in an awn 2 to 5 cms. long. The surface is either glabrous or hairy. In each spikelet the number of flowers varies. Usually two grains, sometimes three, and very rarely four mature in a single spikelet.

Flower:

Sessile, bracteate two bracts -a lemma (inferior palea) and a palea (superior palea). They are situated opposite to each other. The lemma is somewhat boat-shaped with many nerves. The upper margin is notched and ends in a pointed awn. The colour of lemma is greenish white, sometimes pink.

The palea is a thin membranous bract just opposite the lemma. It is slipper- shaped with two prominent nerves. The flower is small, zygomorphic, hermaphrodite, hypogynuous, incomplete, irregular and not showy.

Perianth:

The perianth is represented by two thin membranous structure, the lodicules. They are colourless, narrow and scale-like, and sometimes hairy.

Androecium:

Three stamens. The filaments are long, slender and free; the anthers are bi- celled and versatile.

Gynoecium:

Single median carpel (monocarpellary). The ovary is superior, unilocular, hairy and triangular. From the tip of the ovary two styles arise, stigma feathery. Single ovule, basal placentation.

Fruit:

A caryopsis, the seed coat firmly united to the ovary wall.

Seed:

Albuminous.

Generic characters:

Ligule and auricles present, inflorescence spike of spikelets, two rows of lateral spikelets on the axis and a single terminal spikelet, lemma boat shaped, palea slipper shaped.

2. Hordeum vulgare; Verna.-Jau:

Habit:

Annual herb, annual winter cereal crop (in India).

Root:

Adventitious, fibrous, branched. The whole root system may be divided into two types of roots, the seminal roots and the adventitious roots. The seminal roots are branched throughout their length and penetrate to a depth of 5 to 6 feet.

The true adventitious roots arise from nodes near ground level. They are un-branched and comparatively thicker. They also penetrate to a depth of 3 to 5 feet. Their colour is white and covered throughout their length by root hairs.

Stem:

Erect, cylindrical, fistular, and solid at nodes, 5 to 8 conspicuous nodes. Branching by tillers (tillers develop fewer than wheat). Usually glabrous and covered by leaf sheaths.

Leaves:

The leaf can easily be divided into two parts, the leaf sheath and the leaf blade. The leaf sheath covers the stem and inserted at the node, glabrous and parallel veined. The leaf blade is long, linear lanceolate, acuminate, somewhat hairy, margins also hairy, multi-costate parallel venation. At the junction of the leaf sheath and the leaf blade a prominent ligule and well developed auricles are present.

Inflorescence:

Spike of spikelets. The inflorescence is a cylindrical spike carrying an alternating series of spikelets. The main rachis is compressed and truncate. The rachis consists of a series of straight joints whose ends are more or less flat and upon these flat cushions the spikelets are inserted. The rachis at the base of the ear is surrounded by a ridge of tissue which has been termed the ‘collar’.

Spikelet:

There are two long narrow bracts, almost parallel to each other at the base of the spikelet. These bracts may be considered as glumes. Behind these glumes the solitary flower is inserted, enveloped in lemma (inferior palea) and palea (superior palea).

The lemma is broad, rounded on the back, 5-nerved and with a barbed awn. The innermost bract known as palea (superior palea) is less obvious, narrow and mostly covered by enveloping lemma. It is awn-less and two ridged.

Flower:

Sessile, zygomorphic, irregular, hermaphrodite, incomplete, hypogynous.

Perianth:

The perianth is represented by two small membranous lodicules, arranged opposite the palea.

Androecium:

Three stamens; filaments long, slender, free; anthers 2-celled, versatile.

Gynoecium:

Carpel one (monocarpellary); ovary superior, unilocular, single basal ovule, more or less ovate; two feathery stigmas.

Fruit:

A caryopsis with pointed ends, usually invested by lemma and palea.

Seed:

Albuminous.

Generic characters:

Prominent ligules and well developed auricles present; inflorescence spike of spikelets, cylindrical spike carrying alternate series of spikelets; the ‘collar’ present at the base of rachis, each spikelet represented by a single flower, two long narrow bracts (glumes) with each spikelet; caryopsis usually invested by lemma and palea.

3. Oryza sativa (Rice-Chawal):

Habit:

Annual herb, cultivated as annual cereal in both tropical and temperate regions. Also sown upto 6,000 feet in Himalayan region (but in extremely humid conditions). This cereal crop is always sown under water and in the rain faded areas. In India, Bengal and Bihar are under rice cultivation. Usually the rice is cultivated in lowland areas.

Root:

The whole root system can be divided into two parts, the seminal or primary roots and the adventitious or secondary roots.

The adventitious roots arise from the lower nodes of the plant and its tillers. They are fibrous and branched.

The rice grown in the deep waters, possess adventitious roots at the nodes above ground level.

Stem:

Erect, cylindrical, hollow except at nodes, 6 to 8 mm. thick, nodes and internodes conspicuous, the number of internodes may vary from 10 to 20, branching by tillers.

Leaf:

They always emerge from the nodes, so the number of leaves on an axis is equal to the number of nodes. A normal leaf possesses the leaf sheath, ligule, auricles and the leaf blade (lamina). The leaf sheath always encircles the internode from the node (pulvinus) upwards. The leaf sheath is split at the base, finely ribbed, glabrous.

The ligule is well developed, membranous, colourless or pink coloured. The auricles are well developed; sickle shaped 3 mm. in length, present at the junction of the sheath and the blade (lamina). The leaf blade is long, narrow, lanceolate, acummate, usually pubescent, parallel venation with a distinct midrib. The uppermost leaf the flag is always shorter and broader than the lower leaves.

Inflorescence:

A terminal panicle. The inflorescence borne on the peduncle or on the uppermost internode. Usually the inflorescence is partly covered by leaf sheath; in extreme case it is fully covered. The main axis or the rachis of the panicle is slightly angular, more or less glabrous, somewhat hairy at the nodes.

It may be erect or curved. One to many branches are given out from each node of the rachis. The panicle may be compact or loose. On the end of each branch the spikelets are borne.

Spikelets:

The spikelets are borne either singly on the ends of the branches or in clusters of 2 to 7. The number of spikelets on a panicle varies from 50 to 500. Each spikelet is short pedicelled, generally single flowered, vei7 rarely two flowered. The apex of the pedicel is enlarged and oblique and is termed as facet.

On the facet two glumes occur one outer and the other inner. The glumes are small, lanceolate, shiny, coriaceous approximately equal in size, coloured or colourless (white, yellow or pink).

Flower:

Bracteate, a large conspicuous bract, the lemma. The lemma is boat shaped, 5-nerved and hairy on the nerves. The apex is pointed and usually prolonged into an awn. On each side of the apex or awn two tooth like projections. Lemma is usually pigmented (coloured). The palea is situated just opposite the lemma; it is also boat shaped and 3-nerved.

The end point of the palea develops into apiculus. The apiculus is usually pigmented (purple coloured).

The flower is zygomorphic, hypogynous, irregular, incomplete and sessile.

Perianth:

The perianth is represented by two broad, thick and fleshy lodicules.

Androecium:

Six stamens, arranged in two regular whorls. The filaments are long, slender and free; anthers bi-celled, versatile.

Gynoecium:

Single carpel (monocarpellary); ovary superior, unilocular, longer than broad, single ovuled, anatropous ovule; basal placentation; the ovary is surmounted by two long styles with feathery stigmas; the styles develop from carpellary wall and not from the apex.

Fruit:

A caryopsis. The mature grain is enclosed in the lemma and palea. The grain may be firmly placed or more or less loose inside the husk.

Seed:

Albuminous.

Generic characters:

The ligule is well developed, membranous and sometimes pink coloured, the auricles are well developed and sickle shaped; inflorescence a terminal pancile, rachis of panicle is angular, the flat apex of the pedicel is termed as “facet”. Six stamens. Caryopsis enclosed in lemma and palea (husk).

4. Sorghum vulgare; Verna.-Jowar:

Habit:

All grain producing Sorghums are annual. They are herbaceous and sown in rainy season.

Root:

The root system may be divided into two parts, the seminal roots (primary roots) and the adventitious roots (secondary roots). The seminal roots develop first and penetrate vertically downwards in the soil. The adventitious roots develop from the basal nodes of the stem and extend both vertically downwards and horizontally.

The adventitious roots are fibrous and very well developed. They are profusely branched. Stilt roots are also present usually above the ground level.

Stem:

Erect, solid, several feet high, slightly furrowed on alternate sides. The nodes and internode s are short at the base and longer above. The terminal internode which bears head is longest of all; those of middle region are equal in length. Branching by suckers, each sucker may develop into a head. At each node there is bud except the terminal node.

Leaves:

Simple, alternate, sessile; long, lanceolate; acuminate, surface glabrous, flat, distinct sheathing base (leaf sheath), the margins of leaf sheath are membranous and overlapping, amplexicaul, multicostate parallel venation with a very well developed mid-rib. Ligule, the ligule is short, membranous and fringed, present at the junction of the leaf sheath and the leaf blade. The surface of leaf blade is glabrous.

Inflorescence:

Usually compact panicle, sometimes loose and spreading panicle. The main axis of rachis narrow towards the apex and it is not identified in the terminal and sub-terminal branches. The rachis is somewhat angular and furrowed, hairy at the nodes.

The internode s may be hairy or may not. At the nodes, lateral branches may develop into whorls or in spirals. Each lateral branch may re-branch and on the ultimate branch-lets one to many paired spikelets are produced. The lateral branches are somewhat angular and hairy at the base and at the axils; sometimes the heads (panicles) become inverted.

Spikelets:

The spikelets usually occur in pairs on the lateral branches of panicles, but sometimes they occur in three towards the tip. When the spikelets are in pairs, one is sessile and perfect while the other one is pedicelled and staminate (male). When they are in threes, one is sessile and perfect while the rest two are pedicellate and staminate (male).

Fertile (perfect) spikelet:

The fertile or perfect spikelets are comparatively larger than the staminate spikelets. They may be ovate, oval, elliptical or obovate. Each fertile spikelet possesses two glumes approximately equal in size. Both glumes are nerved.

The nerves are more conspicuous on the outer glume than those of the inner one. The outer glume partially encloses the inner one which is narrow and pointed towards the apex. They are thick, hairy and with membranous margins.

Flower:

On each spikelet there are two florets (flowers) found within the two glumes. The lower floret is sterile while the upper one is perfect. There is a lemma (inferior palea) of lower floret which also partially envelops the perfect floret. The lemma is usually broad, hairy and membranous.

The second and perfect floret has a lemma which is membranous and hairy and two cleft at the apex. In the protruding cleft an awn arises. The palea is usually small and thin.

The flower (perfect) is sessile, bracteate, zygomorphic, irregular and hypogynous.

Perianth:

The perianth is represented by two short and broad, truncate and fleshy, hairy lodicules.

Androecium:

Three stamens; the filaments are free; anthers bi-celled, versatile.

Gynoecium:

Single carpel (monocarpellary); ovary superior, unilocular, with single basal anatropous ovule; basal placentation; two long styles ending in short bushy stigma.

Staminate and Pedicellate Spikelet:

The spikelet is narrower than the sessile one; the pedicel is hairy on the margins; two glumes enclose the two florets (flowers). The lower floret is represented by the lemma only; the upper floret is staminate, with short awned lemma; palea absent; two lodicules; three stamens; pistil absent.

Fruit:

A caryopsis, vary in shape and colour usually white or pale.

Seed:

Albuminous.

Generic characters:

Fringed membranous ligule, no auricles; inflorescence loose or compact panicle, rachis angular and furrowed and hairy at nodes, spikelets in pairs on lateral branches, one spikelet is sessile and perfect while the other is pedicelled and staminate, two florets in each spikelet, one fertile other sterile, usually a white oval caryopsis.

5. Zea mays; Eng.-Maize; Verna.-Makka:

Habit:

An annual cereal, usually cultivated for its food-grains.

Root:

The roots are fibrous and may be divided into three types:

(1) The seminal roots,

(2) The adventitious roots, and

(3) The prop or stilt roots.

The seminal roots penetrate deep in the soil and are branched profusely. The adventitious roots develop from the nodes near ground level; they run horizontally in the ground and are also profusely branched. The colour is either brown or white.

The stilt or prop roots arise from the nodes sufficiently above the ground level. The nodes may give out the whorls of prop roots. These roots are thicker and stronger than the normal roots, and somewhat pigmented.

Stem:

Erect, several feet long, well defined nodes and internode s, the stem is thickened at the base of nodes. Both nodes and internode s are solid. The stem is furrowed on the other side of the leaf, position of furrow alternates at each node.

The last node ends in the tassel. Branching sometimes by tillers. A bud is formed in the axil of each leaf; the buds near ground level develop into tillers while at higher levels they form the ‘pistillate branches’.

Leaves:

Sessile, simple alternate. The leaf may be divided into four parts, the leaf sheath, the leaf blade, the ligule and the auricles. The leaf sheath encloses the internode (amplexicaul). It is entire below and split above. The surface may be glabrous or hairy. The margins glabrous below and hairy above.

The leaf blade is thin, flat, ribbon like, acuminate, lanceolate, parallel venation with a thick and prominent mid-rib. At the junction of the leaf sheath and the leaf blade is membranous, colourless, quarter of an inch long ligule is present. At the junction there are two lateral outgrowths, the auricles.

Inflorescence:

Maize is monoecious, diclinous, i.e., the stamens and pistils are borne on separate inflorescences, but on the same individual plant. The male flowers are carried on terminal panicles known as “tassel”, while the female flowers are on the “ear”.

Staminate or Male Inflorescence:

The male or staminate inflorescence is a panicle at the top of the plant; the panicle consists of a central axis and lateral branches of it; the central axis bears several rows (4 to 11) of paired spikelets, while the lateral branches have only two rows of paired spikelets, one sessile and the other pedicelled.

Pistillate or Female Inflorescence:

The bud found in the axil of foliage leaf develops in the pistillate inflorescence. Sometimes two and very rarely three buds may develop. In structure the pistillate inflorescence is somewhat similar to the main shoot. All its internodes became very short. The uppermost internode is shortest while the lower ones are progressively bigger in comparison. The leaf at the basal node is the prophyllum.

The outer leaves constitute the ‘husk’ and protect the ‘ear’. These protective leaves may be termed as bracts or spathes. Each spathe or bract is a modified leaf possessing leaf sheath, blade and ligule. The ear is a modified spike with thickened central axis, the ‘cob’.

The ‘cob’ carries a series of a paired spikelets in longitudinal rows. Each row of paired spikelets develops two grains, and so the rows of grains are always in even number.

Staminate or Male Spikelets:

The paired male (staminate) spikelets are quite similar to each other except that one is sessile and the other is pedicelled. At the base of each spikelet there is a pair of glumes. The glumes are somewhat longer than the spikelets and near-about equal in size.

They are glabrous but hairy at magins, nerved (7 to 12 nerves). The outer or the lower glume overlaps the inner or upper one. The apex is acuminate. Within each two glumes there are two staminate florets (flowers) borne on a short common rachilla.

Staminate or Male Flower:

Bracteate, the outer bract is the lemma, while the inner one is the palea. The lemma is oval, concave 3-nerved, glabrous, and hairy at margins with somewhat rounded apex. The palea is inserted on the opposite side of the lemma.

It is thin, membranous, 2-nerved flat and with incurved margins. In the upper flower the palea is larger than lemma while in the lower it is vice versa. The flower is sessile, zygomorphic, unisexual, and male.

Perianth:

The perianth is represented by two fleshy lodicules. They are inserted opposite the lemma and alternate with the stamens.

Androecium:

Three stamens (one opposite the palea, remaining two opposite the lemma); the filaments free and short, anthers bilobed, versatile, purple in colour, dehiscence, by a slit at the terminal end.

Gynoecium:

Absent, represented by a rudiment.

Pistillate or Female Spikelets:

The pistillate paired spikelets are arranged completely in rows on the axis or cob. Both the spikelets are sessile and quite similar to each other. There are two glumes at the base of a spikelet. The glumes are thin and membranous and somewhat thicker near the base of the ovary. Each spikelet consists of two flowers, the lower is sterile and the upper one is fertile.

Flower:

Bracteate, the bracts are represented by lemma and palea. The lemma is short, broad and membranous. The palea resembles with lemma, equal or sometimes bigger than lemma.

Perianth:

Usually absent, sometimes represented by two small, scaly lodicules.

Androecium:

Absent, sometimes rudiments of three stamens may be visible.

Gynoecium:

Single carpel (apparently) it is the product of 3 carpels, two extend to form silk and the third bears ovule. Ovary superior, dome shaped, ends in a fine thread like structure, the silk. The silk may be several inches long, style filiform, stigma long and hairy. Ovary single ovuled, campylotropous ovule, basal placentation.

Fruit:

A caryopsis.

Grain:

Albuminous.

Generic Characters:

Ligule and auricles present; inflorescence, monoecious, male inflorescence panicles- ‘tassel’, female-ear; style and stigma long and hairy (silk); ovary dome shaped.

Economic Importance of Family—Gramineae:

From the standpoint of its economic value, this family is most important. It contains all the cereals, grasses, bamboos, canes and other plants.

A list of important plants is given below:

1. Triticum aestivum; Syn. T. vulgare, Eng.-Wheat; Verna.-Gehun-This is a herb, cultivated as a food crop. The wheat straw is used as cattle fodder and in the manufacture of paper. It is mainly grown in Uttar Pradesh, the Punjab, Madhya Pradesh, Maharashtra, Bihar and Rajasthan.

2. Triticum dicoccum; Eng.-Emmer; Verna.-Gehun-It is cultivated as a food crop.

3. Triticum durum; Eng.-Durum wheat; Verna.-Gehun-This is cultivated mainly in Maharashtra as a cereal crop.

4. Triticum sphaerococcum-, Eng.-Indian dwarf wheat; Verna.-Gehun-This is grown as a grain crop mainly in the Punjab.

5. Hordeum vulgare; Syn.-H. sativum-, Eng.-Barley; Verna.-Jau.-This is a herb, cultivated as a food crop mainly in Uttar Pradesh, the Punjab, Rajasthan, Madhya Pradesh, Bihar and West Bengal. The leaves and stems are used as fodder. The addition of 1 or 2 ppm of gibberellic acid to barley is claimed to improve maltin.

6. Oryza sativa; Eng.-Rice; Verna.-Chaval, Dhan:- This is a herb, grown as a food crop. The rice straw is used for making strawboards, paper, mats. Rice-bran oil is used for soaps and cosmetics, and as an anticorrosion oil. It is grown all over India.

7. Avena sativa; Eng.-Oats; Verna.-Jai.-It is grown to a limited extent in North-Western Himalayas. The grains are used by poor people as food.

8. Avena sterilis; Eng.-Indian oat. Red oat; Verna.-Jai.-This is a herb used as a fooder. A hybrid has been raised between this and A. sativa. It is grown in Uttar Pradesh, the Punjab, Bihar, Bengal, and Orissa and in the hills of Tamil Nadu.

9. Sorghum vulgare, Syn. Andropogon sorghum-, Holcus sorghum; Eng.-Sorghum; Verna.- Jowar.-The grains are used as food and the stem and leaves are consumed as a cattle fodder. A spirit is distilled from the grain. It is cultivated mainly in Uttar Pradesh, Punjab, Madhya Pradesh, Andhra Pradesh, Maharashtra and Rajasthan.

10. Sorghum sudanense; Eng.-Sudan grass.-This is an annual grass found in Maharashtra, Assam and the Punjab. It is used as a fodder.

11. Sorghum halepense; Syn. Holcus halepensis: Eng.-Johnson grass; Verna.-Baru Kala mucha.-This is a perennial grass, used as fodder.

12. Pennisetum typhoides; Syn. P. typhoideum, Eng.-Pearl millet; Verna.-Bajra.- It is grown for its edible grains. The straw is used as a fodder. It is cultivated in Uttar Pradesh, the Punjab, Andhra Pradesh, Rajasthan and Maharashtra.

13. Pennisetum purpureum-, Eng.-Elephant grass.-It is grown in Assam, Bengal, Bihar, Uttar Pradesh and the Punjab. It is used as a fodder.

14. Panicum miliaceum’, Verna.-Chin, Morha, Anu.-The grains are edible and the straw is used as a fodder. It is grown mainly in Uttar Pradesh.

15. Panicum miliare; Eng.-Little millet; Verna.-Sawa, Kutki.-The grains are edible. The stems and leaves are used as fodder. It is cultivated in Uttar Pradesh and Madhya Pradesh.

16. Panicum antidotale-, Eng.-Blue panicum; Verna.-Bansi, Gunara-This is a tall grass, used as a fodder and also for the fixation and reclamation of sand dunes. It is found in Punjab, Uttar Pradesh and the Western Peninsula.

17. Zea mays-, Eng.-Maize, Corn, Indian corn; Verna.-Makai, Makka, Bhutta.-This is a tall annual herb. It is grown as a food crop mainly in Uttar Pradesh, the Punjab, Madhya Pradesh, Bihar, and Andhra Pradesh, Jammu and Kashmir. The immature cobs are largely eaten after roasting. The grains are also used in making corn starch and industrial alcohol. It is native of South America.

18. Setaria italica, Syn. Panicum italicum-, Chaetochloa italica’, Eng.-Italian millet; Verna.- Kangni, Kangu, Kakun.-It is chiefly cultivated in Andhra Pradesh and Tamil Nadu for fodder and food. It is used as diuretic and astringent also used externally for rheumatism.

19. Setaria glauca; Syn. Panicum glaucum-, Eng.-Cat tail-millet; Verna.-Bandra.-This is a herb, used as a fodder. The grains are also eaten as food.

20. Eleusine coracana-, Eng.-Finger millet, Ragi; Verna.-Mandal, Mandua.-This is a herb, cultivated as a food crop. This is the main food of the farmers in South India; Maharashtra and of hill-men in Northern India.

This is made into cakes, porridge and sweetmeats. A beer is brewed from the grain by the hill tribes. The enzymic extract of the germinated grain can be used for unhearing hides and skins. It is chiefly cultivated in Andhra Pradesh, Tamil Nadu, Kamataka, Orissa, Bihar, Uttaranchal and Maharashtra.

21. Saccharum officinarum’, Eng.-Sugarcane; Verna.-Ganna, Ikh-The stems yield the cane syrup. The by-products of sugar industry are commercially used for various purposes, e.g., molasses is used in cooking, also for rum, industrial alcohol, synthetic rubber.

A mixture of refuge canes and molasses called molas-cuit is used as fodder. Cane refuge is also utilized for manufacturing bag-paper, wrapping-writing and printing papers, and card-board and as fuel. It is chiefly grown in Uttar Pradesh, Bihar and the Punjab.

22. Saccharum spontaneum; Eng.-Thatch grass; Verna.-Kans.-It is used as a sand binder and also for paper pulp. It is found throughout India. The stems and leaves are used for making thatches.

23. Saccharum fuscum-This grass is used for making cheaper grades of papers, wrapping- boards, and other cellulose products.

24. Agropyron repens; Syn. Triticum repens. The decoction of the rhizome is a demulcent and diuretic and used in the treatment of catarrhal diseases of the urino-genital tract.

25. Aristida depressa-The panicles are made into brooms.

26. Aristida setacea-The panicles are used for making brooms and brushes.

27. Arundinaria falcate; Syn. Bambusa falcata; Eng.-Himalayan bamboo-The stems are used for making baskets, arrows, fishing rods and the lining of roofs of houses. It is found in Western Himalayas and Sikkim.

28. Arundinaria spathiflora-This is a small bamboo growing the undergrowth of the fir, oak and deodar forests of the Western Himalayas at an elevation of 6,500 feet to 9,500 feet. The culms are used for pipe stems and baskets.

29. Arundinaria racemosa-It is found in Bhutan and Western Himalayas. The culms are used for making mats and roofs of houses.

30. Arundo donax’, Eng.-Giant reed; Verna.-Baranal, Narhal.-This is a tall perennial grass. The stems are used in the manufacture of baskets, mats, pipes, writing and printing papers. It is chiefly found in Kashmir, Assam and the Nilgiris.

31. Bambusa arundinacea; Syn. B. spinosa; Eng.-Thorny bamboo; Verna.-Bans.-This is a tall woody grass found throughout our country, particularly along river valleys and in most situations. The culms are used for making paper, thatches, etc. The young buds and grains are consumed as food.

32. Bambusa vulgaris; Eng.-Feathery bamboo; Verna.-Basini bans-The split culms are made into mats and baskets and the young buds are consumed as vegetable. It is cultivated in the hotter parts of our country.

33. Bambusa tulda; Eng.-Bamboo; Verna.-Peka-The mature culms are used for manufacturing paper, baskets and fans. The young culms are eaten as vegetable. It is found in Assam and Bengal.

34. Bambusa balcooa; Eng.-Plains bamboo; Verna.-Bhaluka-It is used for building purposes. It is cultivated in Assam, Bengal, Bihar and Uttar Pradesh.

35. Bambusa polymorpha- It is used for making paper, in Bengal and Assam.

36. Cephalostachyum pergracile.-This is a tufted bamboo and frequently found in association with teak. The culms are used for building and mat-making, and cooked rice is often carried in the internode s on a journey.

37. Cymbopogon citrates; Syn. Andropogon citratus’, Eng.-West Indian lemon grass; Verna.-Sugundh rohisha-The leaves yield an aromatic oil which is used in perfumery, cosmetics and as a flavouring substance. It is chiefly grown in Travancore and Malabar.

38. Cymbopogon martini’, Syn. Andropogon martini’, Eng.-Ginger grass; Verna.- Gandhejghas-The leaves are the source of an aromatic oil, which is used in perfumery and cosmetics; This occurs in two varieties known as the Motia and Sofia.

The essential oil, obtained from the Motia variety, is of a superior quality and is referred to as palmarosa oil, while the oil, from the Sofia variety is inferior in quality and is known as Ginger grass oil. Next to Sandalwood and lemon-grass oils, palmrosa oil is the important of essential oils produced in our country.

39. Cymbopogon nardus; Syn. Andropogon nardus; Eng.-Citronella grass; Verna.-Ganjni- The oil known as Ceylon type, obtained from the leaves; is used in perfumery and cosmetics. It is also used in mosquito-repellent preparations. Also used in an infusion, as a stomachic and carminative.

40. Cymbopogon schoenanthus; Syn. Andropogon schoenanthus Eng.-Camel hay; Verna.- Rousa ghas.-The leaves yield an essential oil which is used in perfumery.

41. Cymbopogon winterianus; Eng.-Citronella grass. The oil commercially known as Java type contains high proportions of geraniol, citronella and citronollol and hence used in the synthesis of organic compounds such as synthetic menthol.

42. Cymbopogon flexuosus; Syn. Andropogon flexuosus; Eng.-East Indian lemon grass.-The leaves yield an oil which is used in perfumery and cosmetics.

43. Cymbopogon jwarancusa-The oil smells like peppermint but the yield is low. The roots are used in the treatment of fevers.

44. Cymbopogon caesius; Syn. Andropogon caesius; Eng. Ginger grass-This is a perennial grass. The leaves yield an essential oil, which is used in soap manufacture. The grass is grown in Tamil Nadu and Travancore.

45. Cynodon dactylon; Eng.-Bermuda-grass; Verna.-Doob. This is a perennial grass used as fodder. This is the commonest used for tennis lawns.

46. Dendrocalamus giganteus-This is the largest of the Indian bamboos. It produces culms upto twenty five cm. in diameter. They are used for water-buckets and boxes. It is cultivated in Assam, Bengal and Malabar.

47. Dendrocalamus hamiltonii, Verna.-Kagzi bans-This is a tall tufted grass, used in the manufacture of paper, baskets and mats. It is mainly cultivated in Dehradun.

48. Dendrocalamus strictus; Eng.-Solid bamboo; Verna.-Bans kaban-It is used in the manufacture of paper, baskets and brushes. It is found in Northern India, Madhya Pradesh and South India.

49. Echinochloa colonum; Syn. Panicum colonum; Eng.-Shama millet; Verna.-Samak-The grains are eaten in times of scarcity.

50. Echinochloa crus-galli; Syn. Panicum crus-galli; Eng.-Baryard millet; Verna.-Samak- It is used as a fodder and food crop. It is chiefly cultivated in Maharashtra and Andhra Pradesh.

51. Echinochloa frumentacea; Syn. Panicum crus galli var. frumentacea; Eng.-Japanese millet; Verna.-Sanwa, Sawa-It is used as a fodder and food crop. It is used as a basis of a very potent beer. It is mainly grown in Madhya Pradesh and Uttar Pradesh.

52. Echinochloa stagnina-, Verna.-Banti-It is used as a fodder. The grains are edible. It is found throughout India.

53. Eragrostis curvula-This is an introduced grass from United States. It is grown for erosion control and fodder.

54. Erianthus arundinaceus; Syn. Saccharam arundinaceum; Eng.-Pin reed grass; Verna- Ramsar, Sarkanda-This is a perennial grass. The leaf sheaths yield a fibre which is used for making ropes, twines and paper, and the stems are used for making chairs, stools, tables, baskets and screen.

55. Erianthus munja; Syn. Saccharum munja; Verna.-Munj sentha, Sarkanda, Munja-The stem fibre is used for making baskets, mats and cordage. The leaves are used for thatching, and are also the source of paper. It is also used as soil-binder. It is commonly found in the Punjab and Uttar Pradesh.

56. Erianthus ravennae; Syn. Andropogon ravennae; Saccharum ravennae; Verna.-Moonj- The stem fibre is used for making chairs, muddas, chhappars and ropes.

57. Heteropogon contortus, Syn. Andropogon contortus-, Verna.-Kumeria-This is a common perennial grass used as a fodder and the fibre is made into mats. It is also used to check soil erosion and in the manufacture of paper and board.

58. Imperata cylindrical; Syn. I. amndinacea; Verna.-Ulu.-This is a perennial grass, the stem is used for thatching and a raw material for paper making. The pillows and cushions are stuffed with its fruits. It is also used in soil conservation.

59. Indocalamus wightianus; Syn. Arundinaria wightiana-It is used for making baskets, mats and walking sticks.

60. Phragmites karka- Syn. P. maxima-, Verna.-Narkul.-This is a perennial grass, the stems are made into pipes, and are also used for making writing and printing paper. They are also used for making chairs, baskets and mats.

61. Pseudostachyum polymorphum-This is a shrubby bamboo found in Sikkim, Assam. It is used by tea planters for making baskets. It is also used for making umbrella handles and walking sticks.

62. Urochloa panicoides-A herb used as fodder. The grains are also edible.

63. Urochloa reptans-A herb used as a fodder. The grains are also eaten.

Systematic Relationships:

Bentham and Hooker have included five families in the series Glumaceae, i.e., the Eriocauleae, Centrolepideae, Restiaceae, Cyperaceae and Gramineae. Engler and Prantl have placed the only two families, i.e., Gramineae and Cyperaceae in the order- Glumiflorae.

Hutchinson has placed the family Cyperaceae in the order-Cyperales; and Gramineae in the order- Graminales. Hutchinson has treated the Graminales to be more highly advanced than the Cyperales. According to him both the Cyperales and Graminales have been derived from liliaceous ancestral stocks in a Juncaceae complex.

According to Wettstein the Cyperaceae and Gramineae have been derived on parallel lines from Juncaceae. It is generally agreed that the grasses and sedges are very advanced groups whose simple inflorescence and floral structures represent drastic reductions from unknown ancestral types.

The Gramineae (grasses) and the Cyperaceae (sedges) are not as closely related as was formerly believed to be the case. It has been shown that the Gramineae differ in having terminal flowers whose ovaries evolved from ancestral types having parietal placentation, from that of the Cyperaceae which possess axillary flowers whose ovaries evolved from types having free-central placentation.

The spikelet, present in both the families is now not considered to be homologous and it does not indicate any phylogenetic relationship.