18BZO14A-U5 Bentham and Hooker’s System of Classification

The most important and the last of the natural systems of classification of seed was proposed by two British taxonomists George Bentham (1800-1884), a self trained botanist, and Joseph Dalton Hooker (1817-1911), the first director of the Royal Botanical Garden, Kew (England).They recorded precise description of most of the plants known at that time. Their monumental work which took about quarter of a century for completion was described in three volumes of Genera Plantarum, published in Latin during July 1862 and April 1883. Bentham and Hooker’s system of classification is still used and followed in several herbaria of the world. It is supposed to be the best system for the students to identify plants in the laboratory.

Salient Features of Bentham and Hooker’s system:

1. It is a classification of only the “seed plants” or phanerogams.

2. They described 97,205 species of seed plants belonging to 7,569 genera of202 families starting from Ranunculaceae up to Gramineae.

3. They classified all the seed plants into 3 groups or classes i.e. Dicotyledons (165 families), gymnosperms (3 families) and monocotyledons (34 families).

4. They included disputed orders among Ordines Anomali which they could not place satisfactorily.

5. Monocotyledons were described after the dicotyledones.

6. The dicotyledons were divided into 3 Divisions (Polypetalae, Gamopetalae and Monochlamydeae) and 14 series. Each series again divided into cohorts (modern orders) and cohorts into orders (modern families).

7. The authors did not mention anything about the origin of the angiosperms.

8. Creation of the Disciflorae, a taxon not described by the earlier taxonomists.

9. Among the Monochlamydeae, major taxa, like the series, were divided on the basis of terrestrial and aquatic habits.

10. Polypetalae carries 82 families, 2610 genera & 31,874 species. Gamopetalae carries 45 families 2619 genera & 34,556 species. Monochlamydae includes 36 families, 801 genera & 11,784 species. Similarly Monocotyledons consist 34 families, 1495 genera and 18,576 species.

Merits of Bentham and Hooker’s System: 1. Each has been described either from the actual specimen or preserved herbarium sheets so that the descriptions are detailed as well as quite accurate.

2. The system is highly practical and is useful to students of systematic botany for easy identification of species.

3. The flora describes geographical distribution of species and genera.

4. The generic descriptions are complete, accurate and based on direct observations.

5. Larger genera have been divided into sub genera, each with specific number of species.

6. Dicots begin with the order Ranales which are now universally considered as to be the most primitive angiosperms.

7. Placing of monocots after the dicot is again a natural one and according to evolutionary trends.

8. The placing of series disciflorae in between thalami florae and calyciflorae is quite natural.

9. The placing of gamopetalae after polypetalae is justified since union of petalsis considered to be an advanced feature over the free condition.

Demerits of Bentham and Hooker’s System: 1. Keeping gymnosperms in between dicots and monocots is anomalous.

2. Subclass monochlamydeae is quite artificial. 3. Placing of monochlamydeae after gamopetalae does not seem to be natural. 4. Some of the closely related species are placed distantly while distant species are placed close to each other.

5. Certain families of monochlamydeae are closely related to families in polypetalae, e.g. Chenopodiaceae and Caryophyllaceae.

6. Advanced families, such as Orchiadaceae have been considered primitive in this system by placing them in the beginning. Placing of Orchidaceae in the beginning of monocotyledons is unnatural as it is one of the most advanced families of monocots. Similarly, Compositae (Asteraceae) has been placed near the beginning of gamopetalae which is quite unnatural.

7. Liliaceae and Amaryllidaceae were kept apart merely on the basis of characters of ovary though they are very closely related.

8. There were no phylogenetic considerations

1. Characters of 2. Distribution of Annonaceae 3. Economic Importance Characters of Annonaceae: Wood aromatic, leaves exstipulate, floral parts usually numerous, free spirally arranged; with distinctive enlarged and flat connective; multipistilate, apocarpous.

A. Vegetative characters: Habit and habitat: Trees, shrubs or lianas. Artabotrys climbs by means of hooks. Oil ducts present in the bark, leaves and perianth leaves. Terrestrial and perennial. Evergreen, deciduous, cultivated as well as wild.

Root: Tap, deep and extensively branched.

Stem: Erect, branched, solid, woody, sometimes woody climbers. Leaves – Simple, entire, alternate, exstipulate, distichous, gland dotted.

B. Floral characters: : Often solitary, axillary, sometimes cauliflourous in groups.

Flower: Actinomorphic but zygomorphic in Monodora due to difference in size of petals, hermaphrodite, unisexual in Stelechocarpus, complete, trimerous, hypogynous, perigynous (Eupomatia) spirocyclic, often aromatic.

Calyx: 3, sepaloid, polysepalous, connate at the base, valvate.: Corolla: Petals 6 in two whorls of 3 each, valvate or slightly imbricate. Sometimes no distinction into sepals and petals so perianth in 3 or more whorls of 3 each. Androecium: Stamens numerous spirally arranged on the axis which forms a large convex receptacle, filament short and thick, anthers long, extrorse, truncate connective, bithecous.

Gynoecium: Carpels numerous or a few, usually free, spirally arranged on the raised receptacle, apocarpous, superior, unicarpellary, unilocular; ovules one to many, anatropous; style short or none, stigma small, Monodora (Africa) with syncarpous ovary and parietal placentation.

Fruit: An aggregate of berries, united to form a single compound fruit (Annona squamosa).

Seed: Large, numerous, often embedded in a copious, white fleshy pulp, endospermic.

Pollination: Entomophilous, due to gaudy and scented flowers.

Floral formula:

Distribution of Annonaceae: The family Annonaceae is commonly called Custard-apple family. Rendle included 62 genera and 820 species in this family. Lawrence recognised 80 genera and 850 species. Takhtajan (1966) included 120 genera and 2,100 species in this family. The family is widely distributed in the tropical regions of the world. Some genera are also found in the temperate climates. In India it is represented by 129 species.

Economic Importance of Annonaceae: 1. Food: The fleshy fruits of various Annona specifics are juicy and edible, and also used in preparation of soft drinks and jellies. Recent analysis shows that they contain about 18 per cent sugar.

Edible fruits are also obtained from various species of Annona and Asimina.

2. Timber: Bocagea virgata, B. laurifolia, Cyathocalyx zeylanicus, Duguetia quitarensis, Oxandra lanceolata and Eupomatia laurina yield useful timber.

3. Oil: The flowers of Desmos chinensis furnish ‘Macassar oil’ a perfume. The perfume is also obtained from Mkilua fragrans and specially liked by Arab women.

4. Fibre: The bark of Goniothalamus wightii produces strong fibres.

5. Ornamental: Artabotrys odoratissimus and Annona discolor are grown in garden for their scented flowers. Desmes chinensis is an ornamental tree.

Common plants of the family: 1. Annona squamosa L. – (H. Sarifa or sitafal) custard apple or sugar apple – well known fruit tree.

2. Annona reticulata L. – Bastard apple or Bullock’s heart – a fruit tree.

3. Artabotrys uncinatas – A small climbing shrub with hooked peduncles – and glabarous leaves.

4. Cyathocalyx zeylanicus (H. Hari Champa) – A tall tree with deflexed or horizontal branches.

5. Polyalthia longifolia – The. “Ashok” An ornamental tree.

6. Uvaria cordata (Dunal) – Alston is a climber noted for its cordate leaves and red flowers.

Important Types of Annonaceae: 1. Annona squamosa (H. sarifa or Sitafal, Fig. 26.1):

Habit: A small tree.

Root: Tap, branched.

Stem: Aerial, woody, branched.

Leaf: Simple, alternate, exstipulate, entire, oblanceolate, obtuse.

Inflorescence: Axillary, two or more flowers arise in the axil of each leaf.

Flower: Bracteate, hermaphrodite, complete, actinomorphic, spirocyclic, hypogynous. Calyx: Sepals three, polysepalous, united at the base, valvate.

Corolla: Petals three, polypetalous, fleshy, pale-yellow, valvate.

Androecium: Stamens numerous, spirally arranged on a conical receptacle, filaments short, anthets oblong, adnated, and appendaged.

Gynoecium: Multicarpellary, apocarpous, spirally arranged, superior, each unilocular, ovule one, basal placentation, style short, stigma long, tapering, papillose.

Fruit: An etario of berries.

Floral formula:

Cucurbitaceae: General characters, Distribution, Important plants, Economic importance and Floral diagram

General Information Common name: Cucumber/Pumpkin family Number of genera: This family includes 110 genera and about 640 species Propagation type: Fruit or seed Distribution: The species of this family are distributed throughout the world. In India this family is represented by about 37 genera and 97 species distributed throughout the country. The chief centre of distribution of these members is Eastern Himalayas.

Vegetative characters Habitat: Members of this family are mostly mesophytes and some xerophytes are also known to exist in this family. Habit: The plants are mostly succulent, trailing, decumbent annual or perennial herbs. These plants climb by means of laterally spirally coiled, simple or branched tendrils. Root system: These plants have woody tap root system. Stem: The stem is usually herbaceous, branched, hairy and five angular with two alternate rings of five vascular bundles each. Leaf: The leaves are simple, alternate, exstipulate, long petioled, and frequently cordate. The leaves are often palmately or pinnately lobed. The petioles are often hollow and stipules are absent

Floral characters Inflorescence: Inflorescence is cymose type. It may be axillary and bears a solitary female flower. The male flowers may be solitary or in the form of racemes, corymbs or panicles. The plants are monoecious or sometimes dioecious as in Coccinia cordifolia and Mimordica dioca. Flower: The flowers are yellow or white, unisexual (rarely bisexual), actinomorphic, pentamerous and epigynous (rarely perigynous as in Actinostemma). The thalamus forms a cup above the ovary.

Calyx: The calyx is of 5 sepals forming a tube, which is wholly adnate to the ovary in female flowers. The aestivation is imbricate or valvate.

Corolla: The corolla consists of 5 petals which are united to form a tube or nearly free (Trichosanthes). The corolla is campanulate (Coccinia, Cucurbita), rotate or salver form. The lobes are imbricate or induplicate valvate. Petals are white or yellow in color. The petals are free in Luffa, Trichosanthes.

Androecium: The Androecium is present in the male flowers only. In female flowers it may be represented by staminodes. The Androecium shows much variation. The simplest condition is where 5 free stamens are present (Fevillea, Luffa cylindrica) with dithecous/monothecous anthers. Thladiantha has five stamens with monothecous anthers; the filaments of four stamens are coherent at the base into two pairs, whereas the fifth stands apart. In Lagenaria, Cucumis and Citrullus there are three stamens with one monothecous anther and other two as dithecous anthers. In Cucurbita there are three stamens with twisted anthers and connate filaments In Sicyos the filaments of all stamens are united into a column bearing the curved anthers In Cyclanthera the stamens are united into a column with two ring-like pollen chambers running around the top. Here the anthers dehisce through a single longitudinal slit.

Gynoecium: The gynoecium is present only in the female flowers. It consists of 3 syncarpous carpels with completely inferior or half-inferior ovary. The ovary is unilocular with three intruding and bifurcating placentae which often meet at the center. Thus, ovary becomes spuriously three loculed. Ovary consists of many anatropous ovules in the placenta. They have only one style with three stigmas.

Pollination: The members of this family are mostly bee pollinated and often they need to be hand pollinated. The flowers are small, green and inconspicuous. The flowers may be visited by insects for nectar which is secreted by a cup shaped disc in male and female flowers. When an insect in search of honey inserts its proboscis, then its head is covered by the stamens and gets sprinkled with the pollen. This same insect may visit and transfer the pollen on to the female flower. Fruit: The fruit is fleshy-berry with soft or hard pericarp. This type of fruit is called pepo. It is usually indehiscent, but rarely dehiscent in Mimordica. The shape and size of the fruit varies considerable in various species.

Seed: The seeds are compressed and non-endospermic with straight embryo. The seeds have large and leafy cotyledons. They are dispersed by explosive opening of the fruit. Viviparous germination is seed Sechium.

Important plants of Cucurbitaceae The following is a list of some important members of family cucurbitaceae, arranged alphabetically.

1. Benincasa hispida (White gourd)

2. Citrullus fistulosus (Tinda)

3. Citrullus vulgaris (Water melon)

4. Coccinia indica/cardifolia (Donda kaya)

5. Cucumis melo (Cucumber)

6. Cucumis melo mimordica (Phut)

7. Cucumis melo utilissimus (Kakri)

8. Cucumis sativus (Cucumber)

9. Cucurbita maxima (Red Pumpkin)

10. Cucurbita moschata (Pumpkin) 11. Cucurbita pepo (Field Pumpkin)

12. Cyclanthera sps.

13. Ecballium sps.

14. Langenaria siceraria (bottle gourd; sorakaya)

15. Luffa acutangula (Ribbed gourd)

16. Luffa cylindrica (gourd; neti beerakaya)

17. Mimordica charantia (bitter gourd)

18. Sechium sps. 19. Trichosanthes anguina (Snake gourd) 20. Trichosanthes dioica (Pointed gourd)

Economic Importance of Cucurbitaceae 1. The fruits of some species of Benincasa and Lagenaria with hard pericarp are used for making musical instruments and decorative items.

2. Dried fibrous tissue of fruit rind of these plants is used as loofah sponge.

3. Some of the members like Ecballium, Cyclanthera, Coccinia and Sechium are grown as ornamental plants.

4. The members of this family provide large number of fruits which could be eaten raw or cooked. They are nutritious and tasty. Following are some of the common fruits yielded from the members of this family,

• Benincasa hispida (White gourd)

• Citrullus fistulosus (Tinda)

• Citrullus vulgaris (Water melon)

• Coccinia indica/cardifolia (Donda kaya)

• Cucumis melo (Cucumber)

• Cucumis melo mimordica (Phut)

• Cucumis melo utilissimus (Kakri)

• Cucumis sativus (Cucumber)

• Cucurbita maxima (Red Pumpkin)

• Cucurbita moschata (Pumpkin)

• Cucurbita pepo (Field Pumpkin)

• Langenaria siceraria (bottle gourd; sorakaya)

• Luffa acutangula (Ribbed gourd)

• Luffa cylindrica (gourd; neti beerakaya)

• Mimordica charantia (bitter gourd)

• Trichosanthes anguina (Snake gourd)

• Trichosanthes dioica (Pointed gourd)

1. Characters of Acanthaceae 2. Distribution of Acanthaceae 3. Economic Importance Characters of Acanthaceae: Mostly herbs, shrubs; leaves opposite decussate, exstipulate, inflorescence cymose, flowers bracteate, bracteolate, zygomorphic, hermaphrodite, hypogynous; calyx five or 4 gamosepalous, corolla pentapartite, gamopetalous, often bilipped; stamens 4 to 2 didynamous, polyandrous, epipetalous; carpels two, syncarpous, ovary superior, axile placentation, style simple, stigma bilobed; fruit loculicidal capsule, seeds non-endospermic with jaculators.

A. Vegetative characters: Habit: Plants are mostly herbs, shrubs or a few climbers (Thunbergia)-, some xerophytes (Barleria, Blepharis, Acanthus), aquatic (Asteracantha longifolia).

Root: Branched tap root system.

Stem: Aerial, erect, underground (Ruellia tuberosa), herbaceous or woody, branched cylindrical, node swollen, climbing or twining (Thunbergia), spinous (Barleria).

Leaves: Opposite decussate, simple, exstipulate, petiolate, usually entire, acute apex, hairy, cystoliths are present in the epidermal cells of stem and leaves.

B. Floral characters: Inflorescence: Solitary axillary (Thunbergia), spike (Blepharis) racemes, dichasial or monochasial cymes.

Flower: Bracteate, bracteolate, bracts and bracteolates conspicuous, pedicellate or sessile, and brightly coloured, hermaphrodite, complete, zygomorphic, pentamerous, or tetramerous, hypogynous, nectariferous disc present below the ovary wall.

Calyx: Sepals 4 or 5 gamosepalous, mostly bilabiate, hairy, imbricate, inferior.

Corolla: Petals 2 to 5, bilipped, gamopetalous, variously coloured, imbricate or twisted, inferior.

Androecium: Generally 4, rarely 5 (Penstemon), in some 2 fertile stamens and 2 staminodes, epipetalous, filaments free, dithecous, dorsifixed, alternate with the corolla lobes, one anther lobe may be smaller than the other and unequally placed, anthers sometimes spurred.

Gynoecium: Bicarpellary, syncarpous, superior, bilocular, axile placentation, carpels median, one or more ovules per loculus, style simple, stigma bilobed, disc present below the ovary.

Fruit: Loculicidal capsule or rarely drupe.

Seed: Non-endospermic with hooks (jaculators).

Pollination: Entomophilous.

Floral formula:

Distribution of Acanthaceae: It is commonly known as Acanthus family. It includes 250 genera and 2500 species. The family is chiefly distributed in tropics and sub-tropics. In India 508 species are present.

Economic Importance of Acanthaceae: 1. Medicinal: Many plants of the family are medicinal. Adhatoda vasika and Barleria cristata are used in cough. Roots of Rhinanthus, Ruellia are also used in medicine. Roots of Ecbolium are used in jaundice. Andrographic paniculata is used for liver diseases. Fruits and leaves of Phlogacanthus thyrsiflorus are used for fever. Leaves of Phlogacanthus tubiflorus when rubbed in water yields lather which is used like soap for washing purposes.

2. Ornamental: Many plants are cultivated for ornamental purposes viz., Acanthus, Barleria, Justicia, Thunbergia, Jacobinia, Ruellia, are often used as hedge.

Primitive characters: 1. A few shrubs.

2. Leaves simple.

3. Flowers hermaphrodite, hypogynous.

4. Gynoecium superior.

5. Pollination by insects.

Advanced characters: 1. Plants mostly herbs.

2. Leaves exstipulate and opposite.

3. Flowers zygomorphic.

4. Calyx gamosepalous.

5. Corolla gamopetalous.

6. Stamens epipetalous, 2 ferile and 2 staminodes.

7. Gynoecium bicarpellary, syncarpous.

8. Seed non-endospermic.

Affinities of Acanthaceae: There seems to be agreement among botanist to retain the Acanthaceae as a distinct family. It has been derived from Scrophulariaceae or stocks ancestral to the Scrophulariaceae. Bessey placed it at the top of his Scrophulariales.

But the Acanthaceae differs from the Scrophulariaceae in having bracteate and bracteolate flowers, imbricate sepals of unequal length; loculicidal oaDsule and non-endospermic seeds with jaculators. It is closely related to the Lamiaceae, but distinguished by a number of characters e.g. absence of aromatic smell, typically quadriangular stem, verticellaster inflorescence, gynobasic style, quadrilocular ovary. These are present in the Lamiaceae.

Common plants of the family: 1. Acanthus ilicifolius: A mangrove plant with prickly and handsome flowers.

2. Barleria: Medicinal shrub, bearing two long thorns at each node.

3. Justicia adhatoda (syn. Adhatoda vesica): Decoction of leaves used in cough syrups.

4. Lepidagathis cuspidata: A small bushy shrub.

5. Peristrophe bicalyculata: Branched herb with six-angled stem.

6. Phlogacanthus: Evergreen shrub.

7. Ruellia: Ornamental erect herb.

8. Thunbergia: Climber, producing violet flowers and gives a peculiar smell.

Important Types of Acanthaceae: 1. Barleria prionitis: Habit: A prickly, bushy shrub.

Root: Tap, branched.

Stem: Aerial, erect, woody, solid, ridged and furrowed, green, branched.

Leaves: Simple, opposite decussate, shortly petiolate in the upper region, longer petiolate in lower region, stipulate; stipules intra-petiolar, spinous, elliptical, lanceolate, entire, acute or acuminate, cuneate base, unicostate reticulate.

Inflorescence: Spike, dichasial cyme in lower region.

Flower: Bracteate, bracteolate, bracteoles 6, 2 larger 4 smaller, narrow with spiny tip, sessile, complete, hermaphrodite, zygomorphic, pentamerous, hypogynous.

Calyx: Sepals 4, polysepalous, slightly fused at the base, arranged in 2 whorls of 2 each, two outer bigger, antero-posterior, spine tipped, imbricate, inferior.

Corolla: Petals 5, gamopetalous, creamy yellow, personate, upper lip with 4 lobes, lower with any 1 petal (4/1) imbricate, inferior.

Androecium: Two fertile stamens and 2 staminodes, polyandrous, epipetalous, filaments long, anther dorsifixed, dithecous, introrse.

Gynoecium: Bicarpellary, syncarpous, superior, bilocular, single ovule in each loculus, axile placentation, simple style, cylindrical, stigma simple, bilobed.

Floral formula:

2. Justicia adhatoda (Fig. 83.1) (Syn. Adhatoda vasika):

Habit: A perennial shrub.

Root: Tap, branched.

Stem: Aerial, erect, woody, cylindrical, solid, greenish-yellow, branched, swollen nodes.

Leaves: Opposite, decussate, simple, petiolate, green, exstipulate, lanceolate, entire, acute, coriacious, unicostate reticulate.

Inflorescence: Racemose, spike.

Flower: Bracteate, bracteolate, sessile, complete, hermaphrodite, zygomorphic pentamerous, hypogynous, whitish with pink streaks.

Calyx: Sepals 5, gamosepalous, green, imbricate, inferior.

Corolla: Petals 5, gamopetalous, personate (2/3) posterior lip with 2 lobes, imbricate, white with pink streaks, inferior.

Androecium: Stamens 2, polyandrous, epipetalous, filaments long, hairy at the base, basifixed, dithecous, introrse, anther lobes at unequal height and spurred.

Gynoecium: Bicarpellary, syncarpous, superior, bilocular, one ovule in each loculus, axile placentation, style long, stigma bifid.

Floral formula:

1. Characters of Amaranthaceae 2. Distribution of Amaranthaceae 3. Economic Importance Characters of Amaranthaceae: Plants mostly herbs, a few shrubs, leaves exstipulate and simple; opposite or alternate, hairy; flowers small, incospicuous and usually with bracts and bracteoles, actinomorphic, arranged in spikes or racemes; perianth 2 to 5, uniseriate, green or coloured, free or united; stamens 3 to 5 free, dithecous, antiphyllous (opposite the perianth segments); gynoecium bi or tricarpellary, unilocular with a single basal ovule; fruit one seeded nutlet.

A. Vegetative characters: Habit: Mostly herbs, rarely shrubs or undershrubs (Deeringia), annual or perennial (Bosia, Ptilotus).

Root: A branched tap root.

Stem: Aerial, herbaceous or woody, erect or straggling, cylindrical, or angular, branched, solid, hairy, green or striped green.

Leaves: Simple, alternate or opposite, petiolate, exstipulate, reddish in colour, unicostate reticulate venation.

B. Floral characters: Inflorescence: Axillary or terminal spikes (Achyranthes, Digera). Some times in cymose panicles.

Flower: Bracteate, sessile or sub-sessile, bracteolate, bracteoles two, actinomorphic, hermaphrodite or unisexual hypogynous, small inconspicuous, green or variously coloured.

Perianth: Usually five tepals, free or united, sometimes two or three (Amaranthus), dry membranous, valvate or twisted, sometime, hairy, green or coloured, persistent, inferior.

Androecium: Stamens 5 or 3 (Amaranthus), free or united, staminodes sometimes present, introrse, dithecous or monothecous (Alternanthera). In Achyranthes 5 fimbriated scales alternate with 5 fertile stamens.

Gynoecium: Bicarpellary, or tricarpellary; syncarpous, ovary superior, unilocular, usually one campylotropous ovule; basal placentation; style short or filiform; stigma 2 or 3.

Fruit: Dry one seeded achene or several seeded capsule or one to several seeded berry.

Seed: Endospermic with polished testa, kidney-shaped embryo curved.

Pollination: Mostly anemophilous and in some plants entomophilous.

Floral formula:

Distribution of Amaranthaceae: The family Amaranthaceae is commonly called ‘Amaranth family’. It is a small family comprising 65 genera and 850 species which are chiefly represented in tropical and temperate regions. In India it is represented by 50 species.

Economic Importance of Amaranthaceae: The Amaranthaceae is of little economic importance.

Food: Seeds of Amaranthus caudatus are edible. Amaranthus cruentus and A. frumentacea are raised as cereals by primitive tribes in Tropical Asia. The leaves of Amaranthus viridis, A. spinosus and A. tricolor are also used as vegetables.

Medicinal: Achyranthes aspera is diuretic and purgative. Decoction of Aerua tomentosa is used to remove swellings. The stem and leaves of Alternanthera are used in snake-bite. The flowers and seeds of Digera muricata (syn. D. arvensis) are given for urinary discharges.

Dye: Leaves of Bosia amherstiana yield a black dye. The fruit juice of Deeringia is a substitute for red ink.

Weeds: Some genera are weeds e.g. Amaranthus, Celosia, Digera, Achyranthes, Gomphrena etc.

Ornamentals: Celosia cristata (Cockscomb), Gomphrena globosa (Globe amaranthus) are cultivated in gardens.

Primitive characters: 1. Plants under-shrubs or shrubs (Bosia, Ptilotus).

2. Leaves simple and alternate.

3. Flowers actinomorphic, hypogynous and hermaphrodite.

4. Anthers dithecous.

5. Seeds endospermic.

Advanced characters: 1. Plants mostly herbs.

2. Leaves exstipulate, opposite (Gomphrena, Alternanthera). 3. Flowers small, inconspicuous and unisexual (Aerua, Amaranthus).

4. Perianth gamophyllous.

5. Number of stamens reduced to 2 or 3.

6. Gynoecium bicarpellary and syncarpous.

7. Basal placentation.

8. One ovule in a carpel.

9. Ovule campylotropous.

10. Anemophilous pollination.

Common plant of the family: 1. Aerua javanica: A hoary tomentose under-shrub.

2. Achyranthes aspera: Chaff flowered, common weed of waste places.

3. Alternanthera sessilis: A prostrate herb of damp places.

4. Bosia amherstiana: A glabrous shrub with edible berries.

5. Celosia (Cockscomb): A cultivated herb in different colours.

6. Digera muricata: A wild herb of winter.

7. Gomphrena globosa: Button flower of Globe amaranth, cultivated for deep pink heads.

8. Cyathula tomentosa: Densely woody herb.

Important Types of Amaranthaceae: 1. Amaranthus viridis (H. Chaulai): Habit: Wild or cultivated annual, herb. Root: Branched tap root.

Stem: Aerial, erect, herbaceous, angular, branched, green or striped, hairy.

Leaves: Alternate, simple, petiolate, exstipulate, ovate, entire or repand, acute, hairy or glabrous, unicostate reticulate.

Inflorescence: Axillary or terminal spikes.

Flower: Bracteate, sessile, incomplete, unisexual, actinomorphic, hypogynous, small, green.

Male flower: Perianth: Tepals 3, distinct, ovate, acute keeled, green, valvate, inferior.

Androecium: Stamens 3, free, antiphyllous, anthers dithecous, basifixed, introrse.

Gynoecium may be rudimentary.

Female flower: Perianth: Tepals 2, ovate, green, inferior, valvate.

Androecium: Absent.

Gynoecium: Bicarpellary, syncarpous, ovary superior, unilocular, basal placentation, ovule one; style three, persistent, stigma capitate, hairy.

Fruit: An indehiscent utricle.

2. Achyranthes aspera (Fig. 90.1):

Habit: Wild perennial herb of waste places, 30 to 90 cm high.

Root: Much branched tap root.

Stem: Herbaceous above and woody below, aerial, erect, quadrangular, rough, branched, solid, hairy, green.

Leaves: Opposite, simple, petiolate, exstipulate, obovate, repand, acuminate, both the surfaces hairy, unicostate reticulate.

Inflorescence: Spike; flowers arranged along a pubescent axis that becomes rigid and much elongated during fruiting-as much as 60 cm.

Flower: Bracteate, bracts persistent acuminate, ending in a spine, bracteolate, sessile, complete, hermaphrodite, actinomorphic, hypogynous, small, green. Perianth: Tepals 5, polyphyllous, ovate, persistent, green, glabrous, twisted, inferior.

Androecium: 5 fertile stamens alternating with 5 sterile and fimbriated scale-like staminodes; fertile stamens antiphyllous, anthers dithecous, basifixed, introrse.

Gynoecium: Bicarpellary, syncarpous, ovary superior, unilocular, one ovuled, basal placentation, style filiform, stigma capitate.

Fruit: An indehiscent achene enclosed within persistent perianth.

Seed: Endospermic.

Floral formula:

1. Characters of Lamiaceae 2. Distribution of Lamiaceae 3. Economic Importance Characters of Lamiaceae: Sweet aromatic smell due to essential oils present in sessile glandular hairs; stem rectangular in cross section, leaves opposite decussate rarely alternate, simple, exstipulate with hairs; inflorescence verticillaster; flowers zygomorphic, hermaphrodite, hypogynous, bracteate; calyx gamosepalous, persistent; corolla bilabiate; stamens 4 epipetalous, didynamous; gynoecium 2 four celled by false septum, syncarpous, axile placentation, gynobasic style, seated on lobed disc; fruit schizocarpic carcerulus.

A. Vegetative characters: Habit: Plants are mostly aromatic herbs or shrubs (Leonotis, Pogostemon). Tree habit is found in the Brazilian Hyptis and climbing habit in American species of Scutellaria.

Root: Tap, branched, rarely adventitious (Mentha).

Stem: Aerial, herbaceous, rarely woody, erect or prostrate, quadrangular, hairy, branched, solid or hollow, sometimes underground suckers (Mentha).

Leaves: Opposite decussate, rarely whorled, simple, petiolate or sessile, exstipulate, hairy with aromatic smell, entire, pinnatifid (Perovskia), unicostate reticulate venation. B. Floral characters: Inflorescence: Very commonly verticillaster consisting of a pair of condensed dichasial cymes at each node; often the verticillasters are grouped together in a thyrsus form; rarely solitary (Scutellaria).

Flower: Pedicellate or sessile, bracteate, complete, zygomorphic rarely actinomorphic (Mentha, Elsholtzia), hermaphrodite, rarely unisexual (Nepeta, Thymus), pentamerous hypogynous.

Calyx: Sepals 5, gamosepalous, bilabiate (Salvia, Thymus) campanulate (Teucrium), persistent, valvate or imbricate aestivation. When a bilabiate calyx is present the arrangement of the sepals may be (1/4) as in Ocimum or (2/3) as in Calamintha.

Corolla: The corolla possesses a tubular base which widens towards the mouth. Petals generally 5, gamopetalous and the five teeth are sub-equal and mostly bilabiate. In Mentha a four lobed corolla arises due to the fusion of two upper teeth. When a distinct bilabiate condition is found the arrangement of the petals may be gamopetalous 2/3 i.e. two petals in the posterior upper lip and three in the anterior lower lip (Salvia, Nepeta, Leucas etc.).

In Ocimum, Coleus, Plectranthus etc. the petals arrangement is gamopetalous 4/1 i.e. four petals in the posterior upper lip and only one petal in the anterior lower lip. In extreme cases the arrangement may be gamopetalous 0/5 i.e. all the five petals forming the lower lip so that the corolla becomes one lipped. Aestivation in the petals is valvate or imbricate.

Androecium: Typically only 4 stamens, didynamous (2+2) and posterior stamen is reduced or represented by a staminode; in Calamintha only two perfect stamens are found, two are imperfect and the fifth reduced. In Salvia only two stamens on the anterior side are found; they are characterised by peculiarly long connectives which help in insect pollination stamens generally introrse and dithecous.

Gynoecium: ADVERTISEMENTS:

Bicarpellary, syncarpous, superior, situated on hypogynous honey secreting disc; bilocular becomes tetralocular by the formation of false septum; axile placentation, one ovule in each loculus; style gynobasic (arising from the base of the ovary), stigma bilobed. The gynoecium character is thus uniform without any variation. Fruit: Usually schizocarpic carcerulus or achenes or nutlets rarely drupaceous.

Seed: Non-endospermic.

Pollination mechanism in the Lamiaceae: According to Delpino there are five important characters of the flower affecting the pollination mechanism viz.: (a) The horizontal position of the axis of the flower;

(b) Division of the corolla into an upper and a lower lip;

(c) Position of stamens and stigma below the upper lip which shelters them;

(d) Position of the nectary at the base of the flower below the lower lip whose anterior part forms a platform for insects; and

(e) Well marked dichogamy.

Muller, who is an authority on the pollination mechanism has remarked in this connection that out of the above the first three are generally true but not universal; the fourth is almost universal but dichogamy is not so complete so as to prevent self pollination.

The types of insects visiting these flowers have a remarkable correspondence with the length of the corolla tube. Those with short tubes are pollinated by flies; slightly longer tubed flowers, e.g. Thymus or Origanum are pollinated by bees; Salvia, Lamium, Teucrium with still longer tubes are pollinated by bees as well as other longer tongued insects.

Floral- formula:

Distribution of Lamiaceae: It is commonly called Mint family. The family includes 260 genera and 3200 species of world wide distribution. In India it is represented by 400 species.

Economic Importance of Lamiaceae: 1. Food: Tubers of Stachys sieboldi are edible. Leaves of Mentha viridis, Ocimum basilicum, Melissa officinalis etc. are used as condiments.

2. Medicinal: Many plants of this family are used in medicines. Ajuga bracteosa, Leucas cephalotes are used in fever. Mentha piperata and Thymus serphyllum give Menthol and Thymol respectively, which are extensively used in medicines. Leaves of Ocimum kilimandus charicum give camphor.

Ocimum sanctum and other species of Ocimum are used in various ailments.

3. Ornamental: Several species of Salvia, Coleus, Ajuga, Leonotis, Dracocephalum, Thymus, Lavandula etc. are cultivated in gardens for ornamental purposes.

4. Perfumes: Aromatic oil is extracted from Thymus, Lavandula (Lavender oil), Rosmarinus (Rosemary oil), Calamintha, Pogostemon etc.

5. Dye: Fruits of Lycopus europaeus yield red dye.

Primitive characters: 1. Some members are perennial shrubs.

2. Leaves simple.

3. Flowers hermaphrodite, hypogynous, coloured and scented.

4. Pollination by insects.

Advanced characters: 1. Plants mostly herbaceous.

2. Leaves exstipulate, opposite or whorled.

3. Flowers in distinct inflorescence.

4. Flowers zygomorphic and in some unisexual (Iboza).

5. Calyx gamosepalous and bilabiate.

6. Corolla gamopetalous and bilabiate.

7. Stamens epipetalous and reduced to 2.

8. Gynoecium bicarpellary, syncarpous, axile placentation. 9. One ovule per loculus.

10. Fruit simple.

11. Seeds non-endospermic.

.

Common plants of the family: 1. Coleus aromaticus (H. Ajwain): An aromatic herb with beautiful variegated leaves.

2. Leucas lantana: Herb clothed with white tomentose hairs.

3. Lavandula vera: Aromatic smell; flowering shoots yield volatile oil.

4. Mentha piperata (H. Podina): Cultivated, branching herb, perennate by means of suckers.

5. Roylea: Woody undershrub with white pinkish flowers.

6. Ocimum santcum (H. Tulsi): Sacred plant for Hindus; also used medicinally.

7. Salvia: Cultivated ornamental herb.

8. Thymus vulgaris: Aromatic procumbent shrub; yields oil of much medicinal importance.

Important Types of Lamiaceae: 1. Ocimum santcum (Fig. 85.1):

Habit: A perennial herb with strong aromatic smell.

Root: Tap, branched.

Stem: Herbaceous above and woody below, aerial, erect, solid, quadrangular, branched, hairy with aromatic smell.

Leaves: Opposite decussate, simple, petiolate, exstipulate, ovate, serrate, acute, hairy, unicostate reticulate.

Inflorescence: A verticillaster.

Flower: Bracteate and bracteolate, pedicellate, complete, hermaphrodite, zygomorphic, pentamerous, hypogynous bilabiate, small and pink.

Calyx: Sepals 5, gamosepalous, bilabiate (1/4), posterior or upper lip broad and lower or anterior lip with small sepals; gland dotted, violet green, imbricate aestivation.

Corolla: Petals 5, gamopetalous, bilabiate (4/1), corolla tube short, upper lip of 4 petals and lower of 1 petal; pink, imbricate aestivation.

Androecium: Stamens 4, polyandrous, epipetalous, didynamous 2+2, anthers versatile; anterolaterals are longer and two postero-lateral are smaller, each postero-lateral has elongated connective bearing fertile anther lobe at the posterior side and sterile lobe at the anterior side; dithecous, introrse.

Gynoecium: Bicarpellary, syncarpous, superior, bilocular but becoming tetralocular, axile placentation, one ovule in each loculus; style gynobasic; stigma bifid.

Fruit: Carcerulus.

Seed: Non-endospermic.

Floral formula:

1. Characters of Poaceae 2. Distribution of Poaceae 3. Economic Importance Characters of Poaceae: Mostly herbs, stem jointed, fistular, cylindrical; leaves simple, alternate, sheathing, sheath open, ligulate; inflorescence compound spike; flowers zygomorphic, hypogynous, protected by palea; perianth represented by 2 or 3 minute scales (lodicules); stamens 3, versatile; carpel one, style 2 or 3, stigmas feathery, basal placentation; fruit caryopsis; testa fused with pericarp.

A. Vegetative characters: Habit: Herbs, annuals or perennials or shrubs, sometimes tree like (Bambusa, Dendrocalamus).

Root: Adventitious, fibrous, branched, fascicled or stilt (Zea mays).

Stem: Underground rhizome in all perennial grasses, cylindrical, culm with conspicuous nodes and internodes, internodes hollow, herbaceous or woody, glabrous or glaucous, vegetative shoots are arising from the base of aerial stem or from underground stems are called tillers.

Leaves: Alternate, simple, distichous, exstipulate, sessile, ligulate (absent in Echinochloa), leaf base forming tubular sheath, sheath open, surrounding internode incompletely, ligule is present at the junction of the lamina and sheath, entire, hairy or rough, linear, parallel venation.

B. Floral characters: Inflorescence: Compound spike which may be sessile or stalked. Each unit of inflorescence is spikelet. The spikelets are arranged in various ways on the main axis called rachilla. A compound inflorescence may be spike of spikelets (Triticum), panicle of spikelets (Avena).

The spikelet consists of a short axis called rachilla on which 1 to many sessile or short stalked flowers are borne. The florets may be arranged in alternate or opposite manner on the central axis.

At the base of rachilla two sterile scales, called glumes, are present. The glumes are placed one above the other on opposite sides. The lower one is called first glume and the upper is called second glume. Both the glumes are boat shaped and sterile. Above the glumes a series of florets are present. Each floret has an inferior palea or lemma and above it a superior palea. The lemma frequently bears a long, stiff hair called awn.

Flower: Bracteate and bracteolate, sessile, incomplete, hermaphrodite, or unisexual (Zea mays), irregular, zygomorphic, hypogynous, cyclic.

Perianth: Represented by membranous scales called the lodicules. The lodicules are situated above and opposite the superior palea or may be absent, or many (Ochlandra), or 2 or 3.

Androecium: Usually stamens 3, rarely 6 (Bambusa, Oryza) and one in various species of Anrostis, Lepturus; polyandrous, filaments long, anthers dithecous, versatile, linear, extrorse; pollen grains dry.

Gynoecium: Monocarpellary, according to some authors carpels 3, of which 2 are abortive, ovary superior, unilocular with single ovule, basal placentation, style short or absent; stigmas two feathery or papillate and branched.

Fruit: Caryopsis (achene with pericarp completely united or adherent with the seed coat) or rarely nut (Dendrocalamus) or berry (Bambusa).

Seed: Endospermic and containing a single cotyledon called scutellum, which is shield shaped and pressed against the endosperm.

Floral formula:

Distribution of Poaceae: The family is commonly known as grass family. It is one of the largest among the angiospermic families. It consists of 620 genera and 6,000 species. The members are cosmopolitan in distribution. The plants represent all the 3 ecological types as hydrophytes, xerophytes and mesophytes. In India it is represented by 850 species.

Economic Importance of Poaceae: The family stands first and foremost in respect of economic importance in whole of Angiosperms. The staple food grains of the population of world is derived from Oryza sativa (Rice) and Triticum aestivum (Wheat). They are cultivated from time immemorial.

The family has been divided on economic basis as follows: Food: Triticum aestivum, Oryza sativa, Zea mays (Maize), Hordeum vulgare (Jaw), Sorghum vulgare (Jowar), Avena sativa (Oats), Pennisetum typhoides (Bajra) are cultivated for cereals and food grains.

Fooder: Many grasses as Cynodon dactylon, Panicum, Cymbopogon, Agrostis, Poa are grown for fodder.

Sugar: Saccharum officinarum (Sugarcane; H. Ganna) is cultivated for gur and sugar. Building material: Some species of Bambusa e.g. B. tulda, B. vulgaris are used for scaffolding, thatching huts etc.

Furniture: Species of Dendrocalamus (H. Bent), Arundinaria, Melocalamus are used in manufacture of furniture.

Aromatic grasses: Many grasses yield scented oils which are used in perfumery viz. Vetiveria zizanioides (H. Khus khus) yields vetiver oil from the roots. The roots are also woven into curtains. Andropogon odoratus (Ginger grass), Cymbopogon citratus (Lemon grass), Cymbopogon martini (Geranium grass), Cymbopogon jawarancusa etc. also yield oil.

Medicinal: Phragmites karka, Cymbopogon schoenanthus etc. are medicinal.

Secale cereale is cultivated for infection of its inflorescence by Claviceps purpurea for production of Ergot and for extraction of ergotine. Ergotine is an excellent remedy for uterine contraction.

Paper: It is manufactured from certain species of grasses and bamboos.

Ornamental: Rhynchelytrum repens, Cortaderia selloana and some species of the tribe Bambusoideae are ornamentals.

Besides these a number of grasses are grown to form fine lawns, play grounds etc.

Primitive characters: 1. A few plants arboreal in habit.

2. All florets in a spikelet are fertile.

3. Glumes are persistent.

4. Lemmas are herbaceous and leafy.

5. Stigmas are three.

6. Leaves are simple and alternate.

7. Flowers are hypogynous and hermaphrodite. 8. Seeds are endospermic.

Advanced characters: 1. Plants are mostly herbaceous, annuals and perennials.

2. Leaves are exstipulate.

3. Flowers are arranged in distinct inflorescence.

4. Flowers are small, incospicuous and zygomorphic.

5. Perianth is represented by lodicules.

6. Stamens are reduced to 3.

7. Gynoecium is monocarpellary and unilocular.

8. Basal placentation.

9. Fruit is caryopsis.

10. Seeds are small sized.

Important Types of Poaceae: 1. Triticum aestivum (Fig. 118.1):

Habit: A cultivated annual crop plant.

Root: Adventitious.

Stem: Herbaceous, erect, cylindrical, fistular, with distinct nodes and internodes, unbranched, glabrous, a number of tillers.

Leaf: Simple, alternate, green, exstipulate, entire margin, acute apex, sheathing leaf base, at the junction of leaf-sheath and leaf-blade membranous ligule present, parallel venation.

Inflorescence: Spike of spikelets.

Flower: Bracteate, sessile, hermaphrodite, zygomorphic, incomplete, hypogynous, flower lies between superior and inferior palea.

Perianth: 2 membranous scales – the lodicules.

Androecium: Stamens 3, polyandrous, filament long, anthers dorsifixed when young and versatile when mature.

Gynoecium: Monocarpellary, theoritically tricarpellary, ovary superior, unilocular, single ovule, basal placentation, style short; stigma 2, feathery.

Floral formula: