- Books Name
- ACME SMART COACHING Biology Book
- ACME SMART PUBLICATION
- CBSE Class 11
DESCRIPTION OF SOME IMPORTANT FAMILIES
This includes major distinguishing features and important plants of the family with floral diagram and floral formula.
1. Family Cruciferae (Brassicaceae) :
(1) Inflorescence corymb or corymbose-raceme
(2) Flowers tetramerous
(3) Cruciform corolla
(4) Tetradynamous condition, sometimes didynamous
(5) Bicarpellary, syncarpous, superior ovary, unilocular but becomes bilocular due to false septum or replum, parietal placentation, stigma bifid.
(6) Fruit is silliqua or silicula
Important plants :
(1) Brassica campestris (Mustard)
(2) Brassica oleracea var. botrytis (Cauliflower)
(3) B. oleracea var. capitata (Cabbage)
(4) Brassica rapa (Turnip)
(5) Raphanus sativus (Radish)
(6) Iberis amara (Candytuft)
(7) Capsella bursa pastoris (Shepherd's purse)
(8) Brassica nigra (Black mustard)
(9) Brassica juncea (Indian mustard)
(10) Sissymbrium irio
2. Family Papilionaceae (Fabaceae) :
(1) Stem erect or climbing
(2) Leaves alternate, pinnately compound or simple, stipulate, reticulate venation, leaf base pulvinate.
(3) Flower bisexual, perigynous, zygomorphic.
(4) Sepals five, gamosepalous, imbricate aestivation, odd sepal anterior.
(5) Petals five, polypetalous, papilionaceous (consisting of posterior standard, two lateral wings and two anterior ones fused to form a keel) vexillary aestivation.
(6) Stamen ten, diadelphous, anther dithecous.
(7) Monocarpellary, unilocular, superior ovary with marginal placentation, style single.
(8) Fruit legume or lomentum.
(9) Seed: One to many, non endospermic.
Br. % K(5) C1+ 2 + (2) A1 + (9) G1
Important plants :
(1) Pisum sativum (Garden pea)
(2) Lathyrus odoratus (Sweet pea)
(3) Sesbania sesban -Green manure
(4) Glycine max (Soya bean) -Edible oil
(5) Cajanus cajan (Arhar)
(6) Phaseolus aureus (Moong)
(7) Phaseolus mungo (Urd)
(8) Crotolaria juncea (Sunn hemp) -Fibre from stem
(9) Arachis hypogea (Ground nut) -Edible oil
(10) Cicer arietinum (Gram)
(11) Lens esculenta (Masur)
(12) Dalbergia sissoo (Shisham)
(13) Vida faba (Broad bean)
(14) Glycirrhiza glabra (Mulathi) -Root as medicine against throat infections
(15) Trifolium alexandrium (Berseem) -Fodder
(16) Cyamopsis tetragonoloba (Cluster bean, Gwar)
(17) Trigonella foenum graecum (Fenugreek)
(18) Medicago sativa (Lucerne)
(19) Butea monosperma (Flame of the forest)
(20) Indigofera tinctoria (Indigo) -Dye
(21) Abrus pecatorius (Ratti, Jeweller's weight)
3. Family Compositae (Asteraceae) :
(1) Inflorescence is head or capitulum.
(2) Flowers small, sessile, epigynous and are called florets.
(3) Calyx modified into hair like structure called pappus.
(4) Ligulate (zygomorphic) corolla in ray florets
(5) Tubular (actinomorphic) corolla in disc florets.
(6) Androecium 5, syngenesious, epipetalous, absent in ray florets.
(7) Bicarpellary, syncarpous, inferior ovary, unilocular with basal placentation.
(8) Fruit is cypsela.
(9) Largest and most advanced family of dicots.
Important plants :
(1) Helianthus annuus (Sunflower)
(2) Tagetes patula (Marigold)
(3) Carthamus tinctorius (Safflower)
(8) Helichrysum (Everlasting or paper flower)
(9) Helianthus tuberosus (Jerusalem artichoke)
(10) Parthenium hysterophorus (Congress grass or carrot grass)
4. Family Solanaceae :
(1) Plants mostly herbs, shrubs and rarely small tree.
(2) Stem herbaceous, rarely woody, aerial, erect, cylindrical, branched, solid or hollow, hairy or glabrous (smooth), underground stem in potato.
(3) Leaves alternate, simple, rarely pinnately compound,exstipulate, venation reticulate.
(4) Inflorescence solitary, axillary or cymose as in Solanum.
(5) Flowers bisexual, actinomorphic.
(6) Sepals five, gamosepalous, persistent (Physalis, Brinjal) green or coloured, hairy, valvate aestivation.
(7) Petals five, gamopetalous, valvate aestivation
(8) Stamens five, polyandrous, epipetalous.
(9) Bicarpellary, syncarpous, ovary superior, bilocular with axile placentation
(10) Ovary obliquely placed, placenta swollen with many ovules
(11) Fruit berry or capsule.
(12) Seeds many, endospermous
Important plants :
(1) Solanum tuberosum (Potato).
(2) Solanum melongena (Brinjal).
(3) Solanum nigrum (Black nightshade).
(4) Withania somnifera (Ashwagandha-medicinal plant).
(5) Lycopersicon esculentum (Tomato).
(6) Capsicum frutescens (Shimla mirch).
(7) Capsicum annum (Chilli).
(8) Cestrum nocturnum (Night jasmine).
(9) Brunfelsia hopeana (Yesterday-today-tomorrow).
(10) Datura alba (Datura) .
(11) Petunia auxillaris (Petunia) .
(12) Atropa belladona (Belladona -medicinal plant) .
(13) Physalis peruviana (Raspberry)
(14) Hyoscyamus niger (Henbane)
(15) Nicotiana tobacum (Tobacco)
5. Family Liliaceae :
Commonly called the lily family, is a representative of monocotyledonous plants.
(1) Plants are perennial herbs with underground bulbs, corms, rhizomes.
(2) Leaves are mostly basal, alternate, linear, exstipulate with parallel venation.
(3) Inflorescence is scapigerous cyme.
(4) Flowers bisexual, actinomorphic, hypogynous and trimerous.
(5) Perianth 6, in two alternate whorls, often united into tube, valvate aestivation.
(6) Androecium 6, often epiphyllous.
(7) Tricarpellary, syncarpous, superior, trilocular ovary with many ovules, axile placentation.
(8) Fruit is capsule, rarely berry.
(9) Seeds endospermous.
(10) Unisexual flowers in Ruscus and Smilax
(1) Asphodelus tenuifolius (Piazi)
(2) Allium cepa (Piaz)
(3) Allium sativum (Garlic)
(4) Colchicum autumnale (Source of colchicine)
(6) Aloe vera -Medicinal plant
(7) Yucca (Ornamental)
(8) Dracaena (Ornamental)
(10) Gloriosa superba (Dagger plant)
(11) Tulip (Ornamental)
(13) Lilium (Lily) (Ornamental)
(14) Senseviera trifasciata (Mother-in-law's tongue) -Source of 'bowstring hemp'.
6. Family Gramineae (Poaceae) :
Most advanced family among monocots
(1) Inflorescence spike of spikelets (Triticum), panicle of spikelets (Avena).
(2) Flowers small, sessile, surrounded by two scales, lemma (fertile bract, inferior or outer palea) and palea (superior or inner palea) . The lemma bears a long, stiff process called awn.
(3) Flowers zygomorphic, incomplete, hypogynous.
(4) Perianth represented by two or sometimes three lodicules.
(5) Androecium 3 or 6, polyandrous, versatile fixation of anthers.
(6) Monocarpellary, superior, unilocular ovary with basal placentation. Stigma is feathery.
(7) Fruit is caryopsis or nut (Dendrocalamus) or berry (Bambusa)
(1) Avena sativa (Oat)
(2) Triticum aestivum (Wheat)
(3) Sorghum vulgare (Jowar)
(4) Pennisetum typhoides (Bajra)
(5) Hordeum vulgare (Jau)
(6) Saccharum officinalis (Sugarcane)
(7) Zea mays (Maize)
(8) Oryza sativa (Rice)
(9) Bambusa tulda (Bamboo)
(10) Cynodon dactylon (Doob grass)
(11) Secale cereale (Rye)
(12) Vetiveria zizanioides (Khus-khus)
(13) Cymbopogon citratus (Lemon grass)
1. Gynobasic style arises from base of the ovary e.g., Labiatae (Lamiaceae).
2. Defense Mechanisms in Plants
(i) Thorns : e.g., Lemon, Pomegranate, Duranta
(ii) Spines : e.g., Agave Yucca
(iii) Prickles : e.g., Silk cotton tree, Rose
(iv) Stinging hair : e.g., Urtica dioica
(v) Glandular hair : e.g., Jatropha, Boerhaavia, Tobacco
(vi) Stiff hair : e.g., Gnaphalium
(vii) Latex : e.g., Ficus, Nerium , Euphorbia
(viii) Alkaloids : e.g. , Poppy, Datura
(ix) Geophilous habit : e.g., Ginger, Turmeric, Colocasia, Onion
(x) Mimicry : e.g., Arisaema, Sansevieria
3. Light, minute and powdery seeds : e.g., Orchids (smallest seeds), Grasses. Seeds of Moringa, Cinchona and Pinus are winged. Fruits of Acer, Hiptage, Terminalia, Dioscorea and Shorea are winged.
4. (a) Pappus: In membets of Asteraceae, pappus help in wind dispersal called parachute
mechanism. e.g., Taraxacum. Sonchus, Tagetes.
(b) Censer mechanism of dispersal is found in Poppy, Argemone, Antirrhinum .
(c) Rolling mechanism of dispersal is found in Amaranthus, Carthamus. These are called
(d) Winged seeds : Seeds of Moringa, Cinchona and Pinus are winged.
(e) Winged fruits : Fruits of Acer,Hiptage, Terminalia, Dioscorea and Shorea are winged.
5. Dispersal by water or Hydrochory -Fruits and seeds showing dispersal by water have floating devices. e.g.. spongy thalamus in lotus, spongy and fibrous outer walls in coconut and double coconut.
6. Dispersal by explosion or Autochory: Ruellia (dispersal using jaculator), Ecballium (dispersal by fountain mechanism).
7. Leguminosae is divided in three subfamilies -Fabaceae, Caesalpiniaceae and Mimosaceae -The major classifying character between these families are character of corolla and stamens.
8. Entire stem is tuberous in knol-khol (Brassica oleracea var. gongyloides).
9. Plant with largest leaf -Victoria amazonica (victoria lily).
10. Plant with longest leaf -Raphia vinifera (palm).
11. Acaulescent -Plant with reduced stem.
12. Stipule like structures in axis of leaflets are called stipels, e.g., Dolichos.
13. Staminodes (sterile stamens) are characteristically present in family Caesalpiniaceae.
Flowering plants exhibit enormous variation in shape, size, structure, mode of nutrition, life span, habit and habitat.
They have well developed root and shoot systems.
Root system is either tap root or fibrous. Generally, dicotyledonous plants have tap roots while monocotyledonous plants have fibrous roots.
The roots in some plants get modified for storage of food, mechanical support and respiration.
The shoot system is differentiated into stem, leaves, flowers and fruits.
The morphblogical features of stems like the presence of nodes and internodes, multicellular hair and positively phototrophic nature help to differentiate the stems from roots.
Stems also get modified to perform diverse functions such as storage of food, vegetative propagation and protection under different conditions.
Leaf is a lateral outgrowth of stem developed exogenously at the node.
These are green in colour to perform the function of photosynthesis.
Leaves exhibit marked variations in their shape, size, margin, apex and extent of incisions of leaf blade (lamina).
Like other parts of plants, the leaves also get modified into other structures such as tendrils, spines for climbing and protection respectively.
The flower is a modified shoot, meant for sexual reproduction, The flowers are arranged in different types of inflorescences.
They exhibit enormous variation in structure, symmetry, position of ovary in relation to other parts, arrangement of petals, sepals, ovules etc.
After fertilisation, the ovary is converted into fruits and ovules into seeds.
Seeds either may be monocotyledonous or distotyledonous.
They vary in shape, size and period of viability.
The floral characteristics form the basis of classification and identification of flowering plants.
This can be illustrated through semi-technical description of families.
Hence, a flowering plant is described in a definite sequence by using scientific terms.
The floral features are represented in the summarised form as floral diagrams and floral formula.