Grade 11 Botany Note
Morphology of Flowering Plants
Angiosperms: All flower bearing plants are called angiosperms.
1. The angiosperms may be annuals, biennials or perennials.
2. They may be herbs, shrubs or trees.
3. Xylem consists of vessels, tracheid, xylem parenchyma and fibers.
4. They bare flowers for reproduction.
5. Archegonia are absent.
6. Endosperms is formed by triple fusion. Thus, it is a triploid structure.
(a) Hydrophytes: Plants that grow in water or in adequate supply of water are called hydrophytes. e.g . Hydrilla , Nymphaea.
(b) Mesophytes:Plants that grow on land under average condition of water and temperature are called mesophytes. E.g.: Mango tree, Mustard plant.
(c) Xerophytes: plants that grow in dry condition or in scarce of water are called xerophytes. E.g.: Opuntia, Nerium.
The angiosperms are classified into two main groups,
Differences between Dicots and monocots.
(a)Seeds contain two cotyledons.
(b)They are often insect pollinated.
(c)The leaves show reticulate venation.
(d)They usually contain tap root systems.
(e)The leaves are dorsoventrally flattened.
a. Seeds contain one cotyledon.
b. They are Often water pollinated.
c. The leaves show parallel venation.
d. They usually contain adventitious root systems.
e. The leaves are isobilateral.
Difference between Tap root and adventitious root.
Parts of Roots
The extreme part of a root of a root is called root tip. It consists of large number of cell. It is called zone of cell division.
Root hair is a part of a plant which observed water and minerals. The main function of root cap is to protect zone of cell division.
The system of a plant which of row above the soil surface, grow towards light phototropism or negative geotropism is called shoot system.
- Provides support to various parts of a plant like stem, leaf, bud, flower, fruit etc.
- Shoot is generally green is colour in young stage.it consists of nodes and internodes.
- Stem helps to transfer water and minerals from roots to leaves. It transfers food prepared in leaves to storage other growing part.
- Branches produce buds, leaves, flowers, fruits.
There are two types of bud.
ii) Axillary bud
a. Vegetative bud
b. Floral bud
Flower: It is main reproduction part of the plant. It has asexual and sexual reproductive organ.
1. Microspore: pollen grains (male gametes)
2. Megaspores: ovule (ovum i.e. female gametes)
Modification of flowering plants
Modification of Roots: The normal tap root is modified to store the good material. It changes its shape and size due to accumulation of food materials. This is called the modification of root.
Modification of tap root: it is the normal tap root modified to store tha food materials. It changes its shape and size due to accumulation of good materials. According to their shape, they are classified into following types.
- Fasiform root
Modification of adventitious root:
The adventitious roots are modified to perform various functions such as the storage of food, support, assimilation and other important function.
1.For storage of food:
a. Tuberous root
b. Annulate root
c. Nodulated root
d. Fasciculate root
2.For mechanical support
a. Prop root
b. Stilt root
c. Climbing root
Stem is the aerial part of the vascular plant, developing from the plumule and bears branches, leaves and flowers. It is differentiated into nodes and internodes which may not be distinct in some cases.
Habit of the plant:
Nature of the stem is determined by the habitat of plant. The plants are usually classified into different categories according to their life cycle habitat or according to their life cycle.
Herbs: a small plant with soft or non-woody stem.e.g grass
Shrubs: a bushy perennial plant with woody or non woody stem. Branches arise from the base e.g China rose.
Tree: a tall woody plant with woody stem. Branches develop well above the ground level. E.g mango tree, peepal tree.
Annuals: plants that complete their life cycle in one year. E.g. rice, maize.
Perennials: plants that continue their growth for many years. Eg. Mango tree, apple tree etc.
Modification of stem
1. Underground modification: there are always thick and fleshy having a good deposition of good material in them. They are of following types;
a) Rhizome: it is a thick and fleshy underground stem, which grows horizontally near the soil surface. It contains dry scaly leaves at distinct nodes. It bears buds in axils of scaly leaves and a terminal bud. The buds serve for vegetative propagation. E.g. ginger, fern, mint etc.
(b)Tuber: swollen terminal portion of an underground stem is called tuber.it stores a large amount of food matrials in the form of starch. The stem tuber bears a number of nodes called eyes. Each eye bears a few buds.
(c) Corm: it is a short, vertical, fleshy underground stem with a flattened base. It is more or less round and bears several dry, thin scaly leaves. It has distinct nodes and internodes. The corm stores a large amount of food material. It bears an apical bud, which produces shoot with leaves and flowers. E.g. colocasia
(d) Bulb: it is a short underground shoot with many scaly leaves. The food material Is stored in the scaly leaves.
2. Sub- Aerial modification: sub- aerial stems are found in plant with weak stems in which branches lie horizontally on the ground. They are of following types.
a.Runner: it is a long, slender, prostate stem with long or short internodes. e.g. mint, grasses, oxalis etc.
b. Stolon: it is along, slender, lateral branch that aeises from the base of the stem.eg black jasmine etc.
c. Sucker: an obliquely upward growingbranch arises from the underground part of the stem and root.
d. Offset: A horizontal, short, more or less thickened stem. It originates from the axil of a leaf, extend for a short distance and then produce a cluster of leaves above and adventitious roots below. e.g. Pistia, water hyacinth etc.
a.Phylloclade: it is the characteristic features of some xerophytes plant. It is a short, green, flattened or cylindrical branch. It carries out photosynthesis and store water for the plant. It contains several nodes and internodes. The leaves are modified into spines or scales to reduce evaporation. e.g. euphorbia
b. Stem tendril:it is a thin, leaf less thread like, spirally curled branch. It helps weak plat to climb. E.g. passion flower
c. Thorn: stem modified into a hard, often straight, pointed and woody structure. It may bears leaves, flowers in certain plants . The thorn arise in spring as axillary shoot with normal leaves and with a special bud. E.g. lemon
d. Twiner: long slender and branched stem climbing by twisting its body around the support. Eg. Cuseuta
Climbers: A weak climbing on support by means of special structure such as hooks, leaf tendrils, stems tendrils etc.
They are foliose part of the plant. It is usually green in colour and helps in manufacture of good, transpiration, exchange of gases. Leaf is a flattened, lateral outgrowth of the stem or the branch developing from a node. It is a photosynthesis appendage of the plant, bearing chlorophyll. It manufactures food for the whole plant.
Structure of leaf:
i) Leaf base: it is the basal part of the leaf by means of which leaf remain attached to the node of the stem. In some cases leaf base bears lateral outgrowths called stipules.
ii) Petioles: It is a stalk below the lamina. It helps in the attachment of leaf. A leaf with petiole is called petiolate and without is sessile.
iii) Lamina: lamina is flattened, expanded green portion of the leaf. It possesses a number of thin veins. It is the most important part of the leaf, which takes part in food production. It gives off numerous thin lateral veins which branch further to form the veinlets.
Venation of leaf: The arrangement of veins and veinlets in the leaf is called leaf venation. It is mainly classified into two types.
i) Reticulate net-like arrangement of veins is called reticulate venation. It is the characteristic features of dicot leaves. It is further classified into two types.
a) Pinnate: single mid-rib with lateral veins is called pinnate.
b) Palmate: many midribs with lateral veins arising from the petiole. It is also called multicostate reticulate venation. E.g. hibiscus, cucumber etc.
ii) Parallel venation: the arrangement of veins is more or less parallel to each other is more or less parallel to each other. It is also classified into pinnate and palmate types.
3. Shape of leaves:the shape of lamina varies greatly in different leaves.
(a) Linear: long, narrow
(b) lanceolate: much longer than broad.
(c) Round: circular leaf lamina.
(d) ovate:broader base with narrow end.
(e) spathulate: spoon shaped
4. Margins of the leaf:
(a) Serrate: sharp toothed margin, like the teeth of a saw. E.g. Rose
(b) Palmate: margin divided in palm like structure.
(c) Lobed: margin divided into many lobes. e.g. ranunculuc.
5. Apex of the leaf:
(a) Acute: sharp ending apex forming on acute angle. e.g. Mango
(b) Obtuse: blunt or rounded apex.
(c)Acuminate: Apex ending in long, tapering pointed end. E.g. peepal
(d) Cuspidate: terminating in appoint.
(e) Euspidate: apex ending in a long, rigid.
6. Leaf Surface: The leaf surface is of various type and can be different according to the family. Some of them are glabrous, hairy, spiny, rough etc.
7. Texture of the leaf: The textures of leaves are coriaceous, fleshy, succulent, membranous and scarious.
8. Phyllotaxy: Arrangement of the leaves on the stem or in the branch is called phyllotaxy. They are of 3 types,
(A) Alternate: if the leaves are originated form each nodes and alternate from each other than this kind of arrangement is called alternate arrangement. E.g. Mango
(B) Opposite: if the leaves are originated from each nodes and they are in alternate position then this condition is called opposite arrangement.
(a) Superposed: if the leaves pairs at upper and lower nods are exactly in same planes.
(b) Decussate: if the pairs of leaves are lies right angle to each other.
(C) Whorled: if more than two leaves are in the same nodes then this condition is called whorled arrangement. E.g. Nerium
Types of leaves: on the basis of number of leaf blades, they are of two types. i.e. simple leaf and compound leaf.
a. Simple leaf: Leaves having a single leaf blade. The leaf lamina may be whole or incised into various lobes but the incisions never touch the mid rib. E.g. Peepal
b. Compound Leaf: The blade is divided into several segments called leaflets, e.g. rose
Types of Compound Leaf:
1. Pinnately Compound leaf: The leaflets are borne on a central axis in two lateral rows. They may be opposite or alternate. It is further classified into
(a) Unipinnate: A pinnately compound leaf with unbranched rachis. Leaflets arise directly on the rachis, e.g. Cassia
i) paripinnate ii) imparipinnate
(b) Bipinnate: A pinnately compound leaf with branched rachis, leaflets arise on the secondary rachis, e.g. Acacia.
(c) Tripinnate: A pinnately compound leaf with secondary and tertiary branches leaflets arise on the tertiary rachis, e.g. Moringa.
(d) Decompound: Leaflets arise on the ultimate branches, e.g. Coriandrum.
2. Palmately compound leaf: Like the finger of a palm the leaflets arise from a common point.
(a) Unifoliate: A palmately compound leaf having only one leaflet, e.g. Citrus.
(b) Bifoliate:leaf having two leaflets.
(c)Trifoliate: Leaf having three leaflets.
(d) Multifoliate: having more than four leaflets. Inflorescence:
The arrangement of flowers on the floral axis Is called inflorescence. The main supporting stalk of inflorescence is called peduncle and the supporting stalk of a single flower is pedicel.
Classification of Inflorescence: it is classified into two types;
-Racemose or indefinite: The main grows continuously and develops on its lateral sides in acropetal succession, i.e. youngest towards the apical end and oldest towards the basal end. They are classified into following type
a) Raceme b) spike c) spikelet d) catkin e) Spadix f)umbel g) corymb h)compound Umbel i) Head
- Cymose or Determinate: The main axis shows limited growth. It is usually branched. The flower borne in basipetal succession, i.e. oldest towards apical end and youngest towards the base.
Flower is a modified shoot of angiosperm plant, especially for sexual reproduction. The flower consist of an axis or receptacle, on which four types of floral leaves such as sepals, petals, stamens and carpels develop one after another. The flowers develop from a bud known as flower bud in the axil of a small leaf like structure called bract.
The flower has a stalk known as pedicel, by which it is attached to the axis of a stem.
Fig: Flower showing parts
Some descriptive terms of flower:
Bract: a modified small leaf like structure present at the base of flower.
Bracteole: a flower with a bract.
Ebracteate: having no bract.
Bracteolate: flower with bracteole, e.g. Adhatoda
Peadicellate: folwer with pedicel.
Sessile: having no stalk.
Sub-sessile: flower with a short pedicel.
Involucre: a whorl of bracts.
Complete: havingall four flora whorls, i.e. calyx, corolla, androecium, gynoecium.
Incomplete: when anyone of the four floral whorls is absent.
Actinomorphic or regular: a flower which can be divided into tow equal halves by more than one longitudinal planes passing through the centre.
Zygomorphic: which flower Can be divided longitudinally into two equal halves.
Irregular: when flower cannot be divide into two equal parts by vertical plane.
Bisexual(hermaphrodite): flower with male and female reproductive organ in same plant.
Unisexual: plant with either male or female reproductive organ present.
Dimerous: flower with two or multiples of two floral organs.
Trimorals: flower with three or multiples of three floral organs.
Accessory organs: calyx and corolla are often referred to as accessory or non-essential organ.
Essential organs: androecium and gynoecium, as they are directly involve in reproduction.
Perigynous: A cup shaped structure around the gynoecium formed by thalamus, gynoecium which develop at the center of the cup and rest of the floral parts.
Epigynous: flower with inferior ovary when further while other floral parts are inserted, i.e. superior e.g. cucrbita
Parts of a flower:
2. Essential whorl
Calyx: it is the outermost whorl of the flower. It is usually green in color and individual member of the calyx is called sepal. The sepals may either remain green form each other or fused together forming a bell shaped structure.
Caduceus: calyx fall down before the flower opens perfectly. E.g. papaver somniferous.
Decidious: the sepals fall off along with the petals at maturity after fertilization. E.g. Brassica campestris.
Persistent: The sepals persist even after the formation of fruit. It is of two types. Accrecent: a persistent calyx assuming a dried form. E.g. Guava
The second whorl lying just inner to calyx. It is composed of number of leaf like brightly coloured petals. All the petals may remain either free from each other or fused together giving different shapes. Thus, the petals help in pollination by attracting insects.
Like calyx the free petals are known as polypetalous and fused petals are known as gamopetalous.
iii.Infundibuliform (funnel shaped)
iv.Rotate (wheel shaped)
v.Ligulate (strap shaped)
It is the male reproductive organ of the flower. It is made up of one or more stamens. The stamens consist of
a. Filament: it is the slender stalk of the stamen, which bears the anther at its tip. There are four pollen sac produces a large number of pollen grains or microspores. The pollen grains are the male reproductive units.
b. Anther: An anther with two loculus is called dithecous, while in some cases the anther has only one locule and it is called monothecous.
(B) Gynoecium (pistil):
The fourth innermost whorl lying at the center of the thalamus is the female. It is composed of one or more carpels. Each pistil consists of three parts. i.e. ovary, style, and stigma.
The swollen basal part of the pistils Is known as ovary. The ovary may have one or more locules or chambers. Each locule contains on or more ovules on placentae. The ovary gives rise to the fruit and the ovules to the seeds. The slender stalk supporting the stigma is called the style and small rounded or lobed head of the pistil is known as the stigma.
Placentation: the arrangement of placentae and ovules on the ovary wall commonly known as placentation. They are marginal, axile, parietal, central and free central, besal, superficial.
A ripened ovary enclosing seeds is called fruit which is developing after fertilization. When only the ovary of the flower develops into the fruit, is called true fruit. The phenomena in which the fruit develops without fertilization is called parthenocarpy. A fruit mainly consist of two parts, i.e. pericarp and seeds.
Pericarp: it develops from ovary wall.
Seeds: it develops from ovule.
Types of fruit: They are of three types,
1. Simple fruits: a single fruit develops from ovary of a flower with or without accessory parts. They may be dry or fleshy, e.g. pyxis, poricidal.
2. Aggregate fruits: simple fruits developing from an apocarpous pistil of a flower are collected together to form an aggregate fruit, e.g strawberry, rubus etc.
3. Multiple or composite fruits: It develops from entire inflorescence, e.g. sorosis.
The seed is a ripened ovule developed after fertilization consist of an embryo and reserve food surrounded by seed coat. The food may be stored in the cotyledons of embryo in none endospermic or in a special tissue called endosperm.
Structure of dicotyledonous seed
The seed is covered by two distinct layers of seed coats called testa and tegman. Testa is the outer coat which is smooth thick and may be coloured. Tegment is inner coat which is thin membranous and hyaline which provide necessary protection.
Inner to the seed coat is embryo. Dicot embryo consist o0f short axis with cotyledons. The cotyledons are attached laterally to the embryonal axis. The portion of the axis lying outside cotyledons and directed towards the mycropile.The cotyledon store of food materials.
Fig: structure of Dicot seed
Structure of monocotyledonous seed
A maize grain is a single seeded fruit called caryopsis. The seed coat and wall of the food are fused together to form a thin layer around the whole part. Coat surrounds endosperm and embryo. The bigger one is endosperm and smaller is embryo.
Fig: structure of monocot seed
Some Dicot and monocot Families:
Family: curciferae (Brassicaceae)
Distribution:the family, includes 38 genera and 98 species, are found in Nepal.They aredistributedworldwide and mainly grow in temprate and cold parts.Many species are cultivated for vegetable, oil yielding seeds and cosmetic production.
Habit:Most of the plants are annual, biennial or perennial herbs. A few species are small shrubs. .
Root:Usually tap and branched, tap root may also became modified like fusiform root or
Napiform roots: These roots become swollen due to the storage of food.
Stem: Commonly herbaceous, erect, cylindrical, hairy, initially reduced but elongates after vegetative growth and forms floral shoot. Stem is very much condensed.
Leaf: Radical, cauline, simple, alternate, petiolate or sessile, exstipulate, hairy, Lyrate, unicostate, reticulate venation.
Inflorescence: Racemose, generally raceme.
Flower: Ebractate, pedicellate, complete, actinomorphic, rarely zygomorphic, bisexual, tetramerous, cruciform, hypogynous.
Calyx: Sepals-4, polysepalous, arranged in two whole 2+2, imbricate aestrivation, inferior.
Corolla: Petals- 4, polypetalous, cruciform, alternate with sepals, aestrivation valvate or
Androecium: Stamens-6, polyandrous, arrange in two whorls, tetradynamous arrange in two whorls, tetradynamous is main characteristic of the family. Aonther bilobed, basifixed and introres.
Gynoecium: Bicarpellary (2 carpels), syncarpous, ovary is superior, unilocular but becames bilocular due to the development of a false septum, parietal placentation, style short, stigma capitates.
Fruit: Siliqua or silicula.
Floral formula: Ebr. ⃝ ○ K2+2 C4 A2+2 G(2)
1. Brassica campestris (tori)
2. Brassica oleracea (Kauli)
3. Brassica rapa (Gantemula)
4. Brassica nigra (Kali tori)
5. Raphanus sativus (mula)
Distribution:it includes more than 482 genera and 7200 species. They commonly grow in the sub tropical and temperate region. These families of many species are cultivated as important pulses and vegetable.
Habitat: Most of the members of this family are annual, biennial or perennial herbs or climbing, rarely they are shrub and tree.
Root: branched tap root. The roots are usually with nodules containing nitrogen-fixing bacteria like Rhizobium spp. Due to this character the plants are alsocultivated to maintain soil fertility.
Stem: herbaceous or woody, erect or week climber, cylindrical, branched, solid, green and glabrous.
Leaf: alternate or whorled, petiolate, stipulate with foliacious stipule, simple or
compound, leaf lets are modified into tendril in some species, reticulatevenation.
Inflorescence: usually racemose types or solitary.
Flowers: bracteates, pedicellate, zyogomorphic, complete, bisexual, usually pentamerous, hypogynous or perigynous.
Calyx: sepals-5, gamosepalopus, aestivation valvate or imbricate, sometime bell shaped.
Corolla: petals-5, polypetalous, petals unequal, aestivation imbricate, inferior.
Androecium: stamens 10, usually diadelphous (9+1), anther dithecous, basifixed and introres, inferior.
Gynoecium: carpels 1 (monocarpellary) ovary superior, unilocular with many ovules, placentation marginal, and style bent at base, flat and hairy, stigma simple.
Fruit: legume or pod.
Floral formula: Br. %O K (5) C1+2+ (2) A (9) +1 G1
1. Dalbergia sissoo (Sisau)
2. Pisum sativum (Pea)
3. Cajanus cajan (Rahar)
4. Glycine max (Bhatmas)
5. Vicia faba (Bakula simi)
Distribution: Most of the species of the family are distributed in tropical and sub-tropical
region but some are found in temperate region. it is the largest genus consisting
16 genera and 51 species are found in Nepal.
Habit: erect or climbing, herbs or shrubs or rarely soft tree.
Root: Tap root.
Stem: erect, rarely climbing or prostrate, herbaceous or woody, solid or fistular, hairy.
Leaf: cauline, alternate or opposite, petiolate or sessile, exstipulate, entire, simple, rarely
pinnately divided, unicostate, reticulate venation.
Flower: ebracteate, pedicellate or sub-sessile, complete, actinomorphic, hypogynous.
Calyx: sepals-5, gamosepalous, campanulate sometime tubular, inferior, aestivation valvate or
Corolla: petals 5, gamopetalous, campanulate, valvate or twisted aestivation.
Androecium: stamens 5, free, epipetalous, alternate to petals, anther basifixed, dithecous,
introres and inferior.
Gynoecium: bicarpellary, syncarpous, ovary superior, bilocular, many ovules in each locule,
axile placentation with swollen placenta, style short, stigma bilobed.
Fruit: berry or capsule.
Floral formula: Ebr⃝○K(5) C(5) A5 G(2)
1. Solanum tuberosum Alu
2. Solanum melongela Bhenta
3. Lycopersicum esculentum Golvenda
Compositae ( Asteraceae)
Distribution: It is largest family of angiosperms which includes about 1000 genera and about
23000 species, and cosmopolitan in distribution.
Habit: mostly annual or perennial herbs, some are under shrubs.
Root: tap or adventitious.
Stem: erect or prostrate, rarely climbing, herbaceous, woody, solid and fistular.
Leaf: radical or cauline, alternate or opposite or whorled, commonly simple, rarely compounds,
serrate or dendate, acute, unicostate reticulate venation.
Inflorescence: head or capitulum, cyme.
Flowers: Two types of flower found in this family: - a. Disc florets b. ray florets.
A. Disc florets
Flowers: bracteate, sessile, actinomorphic, complete, bisexual, pentamerous and epigynous.
Calyx: represented by 2-3 scales or by hairy or absent.
Corolla: petals 5, gamopetalous, tubular, valvate aestivation.
Androecium: stamens 5, epipetalous, filaments long, equal, anther basifixed, dithecous, introrse
Gynoecium: carpels 2, syncarpous, inferior, unilocular with single basal ovules, placentation
basal, style 1, stigma bifid.
Floral formula: Br. ⃝ ○ K pappus or Scales or absent C (5) A 5 G (2)
B. Ray florets
Flower: bracteate, sessile, zygomorphic, incomplete, unisexual,
Calyx: represented by 2-3 scales or by hairy pappul or absent.
Corolla: petals with 3-5 teeth, gamopetalous, ligulate valvate.
Gynoecium: carpels 2, syncarpous, ovary inferior, unilocular with a
basal ovule, placentation basal, style1, stigma bifid.
Floral formula: Br. %○K pappus or 2-3scales or absent C (3-5) A0 G (2)
1. Helianthus annuus suryamookhi
2. Tagetes patula sayapatri
3. Dahlia tuberose lahure phool
4. Artemisia vulgaris titepati
Newly this family is called Asteraceae.
Most of the species of the family are cosmopolitan in distribution. The plants are commonly found in temperate regions and are also found in tropical and sub-tropical regions. In addition to terrestrial form some are hydrophyte xerophyte and epiphyte.
Habit: annual or perennial herbs, rarely woody, mostly wild, some are cultivated.
Root: adventitious, fibrous.
Stem: erect, prostrate or creeping, commonly fistular, often solid, presence of distinct nodes and
internodes, the stem is called culm.
Leaf: cauline, alternate, exstipulate, sessile, simple and sheathing base covering the inter node.
Leaf blade linear to lanceolate, parallel venation.
Inflorescence: racemose type, spiklet.
Flowers: bracteates, sessile, zygomorphic, bisexual or unisexual, incomplete and hypogynous.
Parianth: absence or mostly represented by two membranous lodicules as in rice, wheat; threein bamboo and one in Malice spp.
Androecium: stamens 3 or 3+3 , rarely reduced to 2 or 1, distinct, filaments slender and long,
anther dithecous, versatile and dehisce by longitudinal slits.
Gynoecium: carpels 1, 2 or 3, syncarpous, ovary rounded, superior, unilocular with a single basal
ovule, style and stigma feathery.
Floral formula: Br.% ○ P2 (lodicules) or absent A3 or 3+3 G (3) or (2) or 1
1. Triticum aestivum wheat
2. Oryza sativa Rice
3. Zea mays Maize