Introduction to Angiosperm

Angiosperm are well developed and highly evolved group of plants in which there is seeds enclosed within the fruit. 

Angios: Enclosed

Sperma: Seeds

Angiosperm is well developed and highly evolved group of plants in which there are seeds enclosed within the fruit. They have well-differentiated root, stem, and leaves and also have well developed vascular tissue.

General characters of Angiosperm

• Smallest Angiosperm: Wolffia (0.1 mm)
• Tallest Angiosperm: Eucalyptus regnans (130.5m-435 ft)
• Largest: Ficus benghalennsis
• Angiosperm is autotrophic in nature, but there are some angiosperms which show heterotrophic nature with either parasitic or saprophytic mode of nutrition. Eg; Parasitic; Cuscuta, Saprophytic, Neottia.
• Angiosperm shows a distinct alternation of a generation with dominating saprophytic phase

Angiosperms show three different forms and habit i.e herb, shrub, and tree.

• Herbs are the small sized plant with soft, weak and pliable stems having less or no branches. Eg; Mustard, Bamboo etc
• Shrubs are medium sized woody bushy plants having branches arising near the base. Eg; Rose, Marigold etc
• Trees are large sized hardly woody plants with distinct trunk having branches arising near the apex.

On the basis of lifespan, angiosperms are of three types:

• Annual: They complete their life within few weeks to one year.
• Biennal: They complete their life within 2 years.
• Perennial: They can survive for more than two years. It is of two types. Those plants which flower many times in a lifetime is polycarpic and those which flowers once in a lifetime is monocarpic.

On the basis of water requirements, angiosperms are of three types:

• Hydrophytes: Hydron means water and phyton mean plants. So, literally, we can say the plant that hydrophytes are the plants that grow the well insufficient supply of water. Eg: Lotus
• Mesophytes: Meson means moderate and phyton means plants. So, plants that grow well in a moderate or normal supply of water is called mesophyte. Eg: Maize
• Xerophytes: Xerox means dry or arid. So, those plants which grow well in dry or arid habitat is Xerophytes. Eg: Cactus

Structure

Root System

Root is the underground descending portion of the plants axis which is white or pale brown in color without nodes, internodes, leaves, and buds. It helps in absorption of water and minerals from the soil and provides attachments to the plants. It is positively geotropic, positively hydrotropic and negatively phototropic in nature. On germination of seed, the radical of embryo gives rise to the first root known as primary root which may or may not continues its growth. On the basis of persistence of primary root angiosperm root can be categorized into two types:

• Taproot
• Adventitious root

Taproot

If the primary root continues to grow and give rise to a secondary and tertiary root successively than it is known as tap root system. It is always underground and is the characteristic feature of dicotyledonous. In this case, the secondary roots grow in acropetal succession. Secondary roots away from the growing tip and younger towards the growing tip.

Adventitious root

If the primary root stops to grow and a cluster of roots arise from the base of the stem or from the parts other than radical of the embryo, then it is known as adventitious root system which may be underground or aerial in nature. It may arise from the base of the stem or from nodes and internodes of a stem, branches, and leaves.

A typical type of adventitious root is known as fibrous root which arises from the base of the stem or from the nodes of a horizontally growing stem which is always underground and is the characteristic feature of monocotyledon.

Modification in root

Sometimes in addition to the normal functions of absorption, conduction and anchorage roots may perform storage of food materials, mechanical support, and vital functions. For this, they get modified structurally/ physiologically which is known as a modification of root. This can be found in both tap root and adventitious root.

Modification of Taproot

In some plants with tap root system, the extra food materials are stored by the primary root due to which the root gets swollen into different shapes on the basis of which they are categorized into four types:

Fusiform root

Root is swollen into a spindle-shaped structure with a broad middle portion that tapers towards upper and lower end. Eg; Raphanus sativus (Radish)

Napiform root

In this type, the root is broad on the upper part that suddenly tapers towards the lower end. Eg: Brassica rapa (Turnip)

Conical root

The root is swollen into a cone-shaped structure with a broad upper part that gradually tapers towards the lower end. Eg; Daucos carota(carrot).

Tuberous root

It is the type of root which is swollen into indefinite shape structure. Eg; Mirabilis jalapa( 4 o'clock plant)

Modification of Adventitious root

For storage of food materials:

In some plants, the extra food materials are stored by adventitious root due to which they become swollen into thick and fleshy structure arising from different parts of the plant body.

Tuberous root

The modified root arises from the node of the prostate stem which occurs singly as a swollen root tube. Eg; Ipoemoeabatatas (Sweet potato).

Fasciculated root

The modified root occurs as a cluster of swollen root tubers arising on the base of the stem. Eg; Dahlia, Asparagus.

Moniliform (Beaded root)

The modified root has alternate swollen and constricted regions giving it a chain of beads like appearance. Eg: Momordica indica(tete karela)

Annulated root

The swollen root consists of a series of annulis or ring-like structures. Eg: Ipecacuanha

Nodulose root

In this type, the tips of roots become swollen into beads like structure.Eg; Curcuma amada.

For mechanical support:

Stilt root

In the plants like Zea mays(Maize), Saccharum officinarum( Sugarcane) obliquely downward growing structures arise from the lower nodes known as stilt root which provides mechanical support against bending force of the wind.

Prop root

In the tropical tree like Ficus benghalensis vertically downward growing structures arise from the aerial branches which after reaching the soil surface start to function as the normal root and provide mechanical support to the aerial branches. This is known as prop roots.

Climbing root

In the woody climbers or vines like Piper betel (Betel vine)(Paan), Pothos species(Money plant) etc hanging roots arise from the nodes or internodes or both parts which twine around and clasp the support to provide mechanical strength to the plant.

For vital functions

Assimilatory roots

In the plants like Trapa natans(Water chestnut) (Panifall), Tinospora cordifolia(gurja) etc green hanging roots arise from the aerial parts which due to the presence of chlorophyll pigments can perform photosynthesis and are known as assimilatory roots.

Epiphytic roots

In the epiphytes like orchids, special types of roots arise from the stem which is covered by the spongy tissue known as velamen that can absorb atmospheric moisture. This moisture is used by the plant to carry on photosynthesis process and is known as the epiphytic roots.

Haustorium or sucking roots

In parasitic plants like Cuscuta small peg-like outgrowths are given off which penetrate the host epidermics and get branched. These branches get inserted in the conducting tissue i.e. xylem and phloem. Thus, the parasitic plant can obtain necessary water minerals and food materials from the host plant. This is known as the hostoria or sucking roots.

Respiratory roots

In the plants growing in saline regions( Mangrove plants) vertically upward growing structure arise from the secondary roots which occur above the soil surface and are known as respiratory roots or pneumatophores. These are provided with minute pores known as pneumathodes through which atmospheric oxygen can be taken in to fulfil the oxygen requirements. Eg; Rhizophora

Stem

The stem is the main axis of the plant body arises from the plumule of an embryo. It bears branches, leaves, and flowers. The stem is characterized by its positively phototropic nature and the presence of nodes, internodes, and buds. On the basis of position, buds can be categorized into two types:

• Apical or Terminal bud occurring at the apex or growing tip
• Auxiliary or lateral bud occurring on the axil of leaf

Modifications of stem

Underground modifications of stem

In some herbaceous plants, the aerial part die off during unfavourable conditions and the reserve food materials are stored in their underground portion due to which they become thick and fleshy. These structures are although underground are considered as the modified stems because they have distinct nodes, internodes, scaly leaves and buds on them.

These underground modified stems can grow into the new plant with the coming of favourable conditions. Thus, they are also known as organs of perennation. Its types are discussed below:

Rhizome:

Rhizome is underground, branched, dorsiventral horizontally growing modified stem having distinct nodes and internodes. Thin and membranous scaly leaves arise on the nodes. Apical as well as auxiliary bud arise on the rhizome which grows into new aerial shoots. Adventitious root arises from the lower surface of a rhizome. Eg; Zingiber officinate (Ginger).

Bulb:

It is spherical, an underground structure having reduced conical stem known as disc in which the internodes are highly compressed and nodes closely arranged. Thick and fleshy scaly leaves arise on the nodes which store reserved food materials. Apical bud is enclosed by the scaly leaves and auxiliary buds are sometimes developed. Adventitious root arises from the lower surface of the stem. Eg; Allium cepa(Onion), Allium sativum (Garlic).

Corm:

It is underground swollen vertically growing modified stem having circular nodes and internodes. Thin membranous and brownish scaly leaves arise on the nodes. Single apical bud is prominent and auxiliary buds are sometimes developed. Adventitious roots arise normally all over the body of the corm. Eg; Colocasia, Croccus sativus(Safron).

Tuber:

Tubers are swollen terminal portions of an underground stem which are covered with a thin corky sheath having lenticels(pores). Many depression known as eyes are present which represent nodes. Thin scaly leaves and buds arise on the eyes or nodes. Adventitious roots are absent. Eg; Solanum tuberosum (Potato).

Sub-aerial modification of stem

The sub-aerial modifications are found in many herbaceous plants with a thin, delicate and weak stem. In such plants, a part of the stem lives underground whereas remaining part of the stem is aerial. These plants bear adventitious roots and aerial branches at nodes. Based on type of growth and part of plant that provides them, it is divided into four types:

Runner:

The runner is a specialized weak stem that has long and thin internodes and the branches creep over the surface of the soil. The branches develop adventitious roots from the lower sides of each node. The aerial branches develop from the axil of the scale leaves at the nodes. The runner gives rise to new plants either from axillary or terminal buds. Eg; Cynodon dactylon (Doobo), mint.

Stolon:

It is a thin layered branch which grows horizontally outward and bears nodes and internodes. It produces adventitious root at the point of contact with the soil. Leaves are distributed all over the stolon due to normal apical growth. Eg; Strawberry

Sucker:

It is the lateral branch which develops from the axillary bud of an underground part of the stem. It grows obliquely and gives rise to leafy shoot. The adventitious root develops at the base of nodes of the underground part of a sucker. Eg; Mentha arvensis (Mint), Chrysanthemum.

Offset:

The offset is also known as condensed aquatic runners. It is weak, elongated, horizontal branches at one internode that arise in the axil of a leaf. An offset produces a tuft of leaves above and a cluster of the roots below. The offset may break off from the parent plant and acts as an independent plant. Eg; Pistia(Water lettuce).

Aerial modifications of stem

Phylloclade:

It is the characteristic feature of some xerophytic plants. Phylloclade can be defined as green, swollen, cylindrical or flattened aerial modified stem of unlimited growth. It has many depressions known as Aereoles representing on the nodes on which reduced leaves or spines and buds are developed. Phylloclade store water in the form of mucilage and is covered by thick cuticle so that the plant can survive in a dry habitat. Eg; Opuntia(Nagphani), Euphorbia royleana(Siundi)

Cladode:

Cladode is short, green aerial modified stem or branch of limited growth having single internode only. It can perform photosynthesis on itself because the leaves are modified into thin membranous scales. Eg; Asparagus racemoscus (Kurilo).

Tendrils:

Tendrils are thin, elongated, thread-like spirally coiled modified stem which may be branched or unbranched and provide support to the climbers. Tendrils arising from the axils of leaves are known as axillary tendrils. Eg: Passiflora (Passion flower). Tendrils arising on the internodes are known as extra-axillary tendrils. Eg; Cucurbita (Gourd). Tendrils arising on the opposite of leaf are known as leaf-opposed tendrils. Eg; Vitis vinifera(Grapevine).

Thorns:

Thorns are short pointed hard often straight aerial, modified stem arising from the axil of the leaf which may be branched or unbranched and may bear leaves or flowers. Eg; Durant repens, Punica granatum(Pomegranate), Bougainvillea.

Bulbils:

Bulbils are modified axillary buds which are meant for vegetative propagation of the plant. They develop from axillary buds, which become swollen and fleshy with food and drop off to form new plants. Eg; Agave.

Leaf

Leaf is a lateral dissimilar appendage of a plant body which arises on the node of stem and bears axillary bud on its axil. It is thin flattened expanded portion considered as the site of photosynthesis. In angiosperm different types of leaves are present such as; cotyledonary leaves, bract leaves, scale leaves etc. The common type of green leaf is known as foliage leaf which consists of three major parts:

• Leaf base
• Leaf stalk or petiole
• Leaf lamina or leaf blade

Leaf base

The point of attachment of leaf with the node of the stem is known as leaf base. Sometimes the leaf base may become swollen and is known as pulvinus leaf base. Eg; Mimosa pudica(Touch me not). Sometimes in monocotyledons, the leaf base becomes expanded and winged which partially or completely covers the internode and is known as sheathing leaf base or leaf sheath.

A pair of small leaf-like structures are known as stipules may occur on either side of leaf base. Leaf with stipules is known as stipulate leaf and without stipules is known as the ex-stipulate leaf. Stipules may be of different types such as;

• linear stipules
• Ochreate
• Foliaceous

Leaf stalk or petiole

The petiole is cylindrical or subcylindrical solid or hollow stalk of the leaf which joins leaf base with the leaf lamina. Leaf with petiole is known as petiolate leaf and without petiole is known as a sessile leaf.

Leaf lamina or leaf blade

The expanded green portion of the leaf is known as leaf lamina or leaf blade which bears midrib, veins, and veinlets. Mid-rib is the main vein arising from the tip of petiole which is known as costus and its number may vary in different cases. If the upper or ventral surface of leaf differs from the lower or dorsal surface than the leaf is known as a dorsiventral leaf which is present in dicots. If the two surfaces are almost same then it is known as an oblilateral leaf which is present in monocots.

Structural Variation in Angiospermic leaf

Structural Variation in Angiospermic leaf

Shape of leaf

Acicular: Elongated pointed needle-shaped leaf. Eg; Pinus

Linear: Elongated, narrow flattened leaf. Eg; Grasses, Zea Hays.

Lanceolate: Elongated sword-like leaf. Eg; Nerium

Elliptic: Ellipse shaped leaf. Eg; Psidium Gwasava (Gawa)

Cordate: Hard shaped leaf or leaf with a notched base and pointed apex. Eg; Piper betel.

Obcordate: Leaf with notched apex and rounded or pointed base. Eg; Bauhinia

Ovate: Egg-shaped leaf or leaf with the broad base and narrow apex. Eg; Hibiscus

Obovate: Leaf with broad apex and narrow or pointed base. Eg; Terminalia

Oblong: Elongated rectangular leaf. Eg; Musa( Banana)

Hastate: Arrowhead-shaped leaf. Eg; upper leaf of Brassica Campestris.

Lyrate: Lyre-shaped leaf or leaf with large terminal lobe and small lateral lobes. Eg; Brassica Campestris

Apex of leaf

Acute: Leaf with a pointed apex.

Obtuse: Leaf with rounded apex.

Accuminate: Leaf with pointed apex in which extreme apex is drawn out into an elongated tale like structure.

Mucronate: Leaf with rounded or pointed apex in which short pointed outgrowth appears at the extreme tip.

Surface of Leaf

Glabrous: Leaf with a smooth or non-hairy surface.

Glaucous: Leaf with the smooth and shiny surface. Eg: Rubber plant.

Pubescent: Leaf with the hairy surface. Eg: Geranium

Margin of Leaf

Entire: Leaf with the smooth margin.

Repand: Leaf with slightly or lightly wavy margin.

Sinuate: Leaf with deeply wavy margin.

Serrate: Leaf with a saw - like margin in which teeth are directed towards the apex.

Serrulate: Leaf with finely serrated margin.

Dentate: Leaf with toothed margin in which teeth are outwardly directed.

Runcinate: Leaf with a saw- like margin in which teeth are directed towards the leaf base.

Texture of leaf

Herbaceous: Thin and soft textured leaf. Eg; Rose

Coriaceous: Thick firm and leathery texture. Eg; Rubber plant

Succulent: Thick and fleshy leaf which stores water in the form of mucilage. Eg; Aloe vera

Duration of leaf

Caducous: Leaves falling off much earlier in the life.

Deciduous: Leaves remaining intact at least for one season.

Persistent: Leaves remaining intact for whole life.

Insertion of Leaf

Cauline: Leaves arising on the main stem. Eg; Maize

Ramal: Leaves arising on the branches. Eg; All trees

Radical: Leaves arising in a cluster or in a rosette form from the reduced stem known as disc than it is known as radical leaves. Eg; Radish, Turnip.

Phyllotaxy

The mode of arrangement of leaves on the node of the stem is known as phyllotaxy. It is of three types;

Alternate/Spiral

If single leaf arises on a node and leaves of adjacent nodes lie alternately to each other then it is known as alternate phyllotaxy. Eg; Tulsi

Opposite

If a pair of leaves arise on a node and lie opposite to each other than it is known as opposite phyllotaxy. If a pair of leaves on adjacent nodes occur on the same plane than it is known as superposed opposite phyllotaxy. If a pair of leaves on adjacent node lie perpendicular to each other than it is known as decussate opposite phyllotaxy.

Whorled:

If a cluster of leaves arises on a node then it is known as whorled phyllotaxy.

Types of leaves

Mainly there are two types of leaves they are;

• Simple leaf
• Compound leaf

Simple leaf

If the leaf lamina is unincised or if incised incision does not reach up to the midrib or up to the tip of the petiole than the leaf is known as a simple leaf. Simple leaf always bears axillary bud on its axil.

Compound leaf

If the leaf lamina is incised into small fragments known as leaflets either up to the midrib or up to the tip of the petiole than the leaf is known as a compound leaf. Compound leaf also bears axillary bud on its axil, but the leaflets never bear axillary buds on their axil.

Compound leaf can be categorized into two types;

• Pinnately compound leaf
• Palmately compound leaf

Pinnately compound leaf

If the leaf lamina is incised up to the midrib so that the midrib gets modified into the rachis bearing leaflets laterally than it is known as a pinnately compound leaf. On the basis of branching pattern of the rachis pinnately compound leaf can be categorized into four types;

Unipinnate:

If the leaflets arise on primary rachis itself than it is known as a unipinnately compound leaf. If there is an odd number of leaflets than it is known as imparipinnately compound leaf and if there is an even number of leaflets than it is known as paripinnately compound leaf.

Bipinnate:

If the primary rachis gets branched once and the leaflet arises on the secondary rachis then it is known as a bipinnately compound leaf.

Tripinnate:

If the rachis gets branched twice and the leaflets arise on the tertiary rachis then it is known as tripinnately compound leaf.

Decompound:

If the rachis gets branched thrice or more than thrice and the leaflets arise on the ultimate branches then it is known as decompound leaf.

Palmately compound leaf

If the leaf lamina gets incised up to the tip of the petiole so that the leaflets appears like the fingers articulated on the palm then it is known as a palmately compound leaf. On the basis of number of leaflets palmately compound leaf can be categorized into five types;

• Unifoliate (with single leaflet)
• Bifoliate (with double leaflet)
• Trifoliate (with three leaflets)
• Quadrifoliate (with four leaflets)
• Multifoliate (five or more than five-leaflets)

Inflorescence

The mode of arrangement of flowers on the floral axis is known as an inflorescence. In angiosperms, a stalk of the flower is known as pedicel. Flower with pedicel become pedicellate flower and without pedicel become a sessile flower. The stalk of the inflorescence is known as the peduncle. Single flowered inflorescence is known as solitary inflorescence is known as solitary inflorescence and many-flowered inflorescences can be categorized into two major types;

• Racemose inflorescence
• Cymose inflorescence

Racemose inflorescence

If the floral axis does not terminate into a flower and its growth continues and give rise to the flowers laterally in acropetal succession (younger towards the growing tip and older towards the base) or In elongated floral axis or centripetal succession(younger towards the centre older towards the periphery) or if flattened floral axis than it is known as racemose inflorescence.

Types of Racemose Inflorescence

Raceme

Pedicellate flowers arranged in acropetal succession in the elongated floral axis. Eg; Brassica Campestris

Spike:

Sessile flowers arranged in acropetal succession in the elongated floral axis. Eg; Amaranthes, Achyranthes.

Spikelet

It is few small flowered spike surrounded by a pair of sterile glumes at the base. Eg; rice, maize, wheat.

Catkin:

In this type, the floral axis is weak and pendulous which bears unisexual sessile flowers in acropetal succession. Eg; Morus alba (Kimbu).

Spadix:

In this type, the floral axis is thickened and elongated which bears sessile flowers in acropetal succession and is surrounded by two too many spathes. Eg; Musa.

Head or capitulum:

In this type, the floral axis is flattened known as receptacle on which small flowers known as florets are developed in centripetal succession and is surrounded by a green involucre of bracts. Eg; Compositae

Corymb:

It is a special type of raceme in which the size of pedicels of the flowers go on decreasing towards the apex so that all the flowers are brought almost on the same level. Eg; Iberis Amara (candytuft)

Umbel:

The floral axis is short or reduced at the tip of which cluster of pedicellate flowers is developed. Eg; Coriandrum (Dhaniya)

Cymose inflorescence

If the floral axis terminates into a flower due to which its growth is checked and it gives rise to lateral branches successively which also terminate in the flowers, then it is known as a cymose inflorescence. Here, the flowers are arranged in a basipetal succession. On the basis of branching pattern, cymose inflorescence can be categorized into three types;

Monochasial or Uniparous cyme

If the floral axis after terminating into a flower gives rise to single lateral branch at a time which also terminates into a flower and follows the same pattern of growth, then it is known as monochasial cyme. Eg; Solanum

If the lateral branches successively arise on the same sides in a helix-like structure then it is known as helicoid cyme. If the lateral branches arise on the alternate side successively in a zigzag manner then, it is known as scorpioid cyme.

Dichasial or Biparous cyme

If the floral axis after terminating into flower gives rise to a pair of lateral branches at the line which follows the same pattern of growing then, it is called Dichasial cyme. Eg; Nyctanthes.

Polychasialor Multiparous cyme

If the floral axis after terminating into a flower gives rise to a cluster of lateral branches at the line which follows the same pattern of growth then it is called Polychasial. Eg; Calotropis

Flower

Flower is the reproductive part of the angiosperm which consists of four whorls i.e.

• Calyx
• Corolla
• Androecium
• Gynoecium

Calyx and Corolla are known as non-essential or accessory whorls because they are not involved in the reproduction. However, they provide beauty to the flower. Androecium and Gynoecium are known as essential or reproductive whorls because they are directly involved in the reproduction. Flowers with all these four whorls is known as a complete flower and that without any of these four whorls is known as an incomplete flower. Flower with both androecium and gynoecium is known as bisexual flower and that without one of these two whorls is known as a unisexual flower.

The small leafy pointed structure known as bract may be present at the base of the flower. Flower with bract is known as bracteate flower and without bract is known as an ebracteate flower. A whorl of bracts is known as involucre. Eg; Sunflower and sterile scaly bracts present at the base of spikelet that encloses flowers is called glume. Eg; Wheat. In some cases, a secondary bract arises at the base of individual flower known as bracteole. The flower with bracteole is called bracteolate.

Symmetry of flower

The divisibility of the flower vertically in two halves is a symmetry of the flower. The symmetry of the flower may be actinomorphic, zygomorphic, asymmetrical(irregular).

Actinomorphic: If a flower can be divided into two equal longitudinal halves from more than one vertical planes passing through the centre then it is known as an actinomorphic flower. Eg; Brassica, Solanum.

Zygomorphic: If a flower can be divided into two equal longitudinal halves from only one vertical plane passing through the centre then it is known as a zygomorphic flower. Eg, Pisum, Lathyrus.

Asymmetrical: If a flower cannot be divided into two equal longitudinal halves from any vertical plane then it is known as an asymmetrical flower. Eg; Canna

Thalamus of flower

The thalamus is the swollen tip of a pedicle or the floral axis on which the floral whorls are developed in a cyclic manner. On the basis of shape of thalamus angiospermic flower can be categorized into three types;

Hypogynous:

In this type, the thalamus is swollen at the topmost position of which lies the ovary and other floral parts arise below the ovary on the thalamus so that the position of ovary becomes superior and other floral parts become inferior. Example; Brassica, Solanum.

Perigynous:

Here the thalamus is cup-shaped in which ovary lies at the central position and other floral parts arise around the ovary on the rim of the thalamus. Due to this, the position of ovary becomes semi-inferior and other floral parts superior in nature. Eg; Rose

Epigynous:

Here the thalamus is cup-shaped with a deep cavity which encloses the ovary and other floral parts arise above the ovary on the thalamus so that the ovary becomes inferior and other floral parts superior in nature. Eg; Tagetes

Perianth of Flower

The perianth is a non-reproductive part of a flower. It contains both calyx and corolla.

Calyx

Calyx is the outermost whorl individual unit of the sepal. Free sepal makes polysepalous condition and fused sepals make the gamosepalous condition. Sometimes sepals instead of becoming green color attain the color of petal and are then known as petaloid sepals.

Duration:

Caducous: Sepals falling off much earlier i.e. before the opening of a flower.

Deciduous: Sepals remaining till the maturity of a flower.

Persistent: Sepals remaining till the maturity of the fruit.

Corolla:

Corolla is a second colored whorl of flower individual unit of which is petals. Free petals make polypetalous condition and fused petals make a gamopetalous condition. Green petals are termed as sepaloid petals

Cruciform corolla:

The presence of four free petals arranged in a cross-like manner and each petal differentiated into the broad limb and pointed claw. Eg; Brassicaceae

Caryophyllaceous corolla:

The presence of five free petals each petal differentiated into an elongated claw and broad limb placed at a right angled to each other. Eg; family Caryophyllaceae

Papilionaceous corolla:

The presence of five unequal sized petals. The posterior largest petals are known as standard or vexillum. Two lateral medium sized petals are known as wings or alae. Two anterior smallest fused petals is known as keels(Carina). These petals give a butterfly-like appearance to the flower. Eg; Pea

Tubular:

Petals fused to form a tube-like structure.

Campanulate:

Petals fused to form bell-shaped structure.

Infundibuliform:

Petals fused to form funnel-shaped structure.

Androecium

The androecium is the male reproductive whorl individual unit of which is stamen. Each stamen consists of fertile anther joined with filament with the help of connective tissue. Anther may be single lobed or bilobed in nature. Single lobed anther is known as monothecous anther and two lobe anther is known as dithecous anther.

Attachment of anther and filament:

Basifixed:

The filament is attached to the base of the anther.

Adnate:

It is also basifixed type in which the connective runs throughout the length of anther and protrudes out from the apex.

Dorsifixed:

The filament is attached to the dorsal surface of another.

Versatile:

Filament just touches the dorsal side of another so that the anther can easily swing.

Length of stamens

Didynamous:

The presence of 4 stamens, 2 with short filaments and 2 with long filaments. Eg; Ocimum ((Tulsi).

Tetradynamous:

The presence of 6 stamens in two whorls, outer 2 with short filaments and inner 4 with long filaments. Eg; Cruciferae

Cohesion of stamens:

If the stamens are free, the condition becomes polyandrous as the stamen has two parts, the cohesion or fusion of stamens occur in different ways which can be categorized into three conditions:

Syngenesious:

Anther is fused, a filament is free. Eg; Compositae

Adelphous:

In this, the filament is fused and anther is free. It is of three types they are:

Monadelphous:

Filaments fused into a single bundle or staminal tube. Eg; Hibiscus

Diadelphous:

Filaments fused into two bundles. Eg; Pisum

Polyadelphous:

Filaments fused to form more than two bundle. Eg; Rosa

Synandrous:

In this type, the stamens are completely fused.

Adhesion of stamens

Epipetalous: Stamens( filaments) attached with the petals.

Gynandrous: Stamens (filaments) attached with the gynoecium.

Gynoecium

The gynoecium is a female whorl individual unit of which is carpel. Carpel is a modified leaf which bears the ovules, a simple pistil or one of the segments of the compound pistil. The pistil is the collective term for ovary, style and stigma. Gynoecium consist of three parts;

• Stigma
• Style
• Ovary

Stigma is the uppermost part which may be simple or lobed or bifid or feathery in nature. Style joins the stigma with the ovary. The ovary is basal fertile portion inside which ovules are developed.Ovary, later on, grows into fruit and ovules into seeds.

Gynoecium with single carpel is known as simple gynoecium and with two or more carpels is known as compound gynoecium which may be apocarpous with free carpels or syncarpous with fused carpels. In syncarpous gynoecium, a number of carpels equal the number of stigma or the number of styles or number of locules in the ovary or number of cluster of ovules in the ovary.

Number of carpels

Monocarpellary: The pistil is composed of only one carpel. eg; Pea

Bicarpellary: A condition when the pistil is composed of two carpels. Eg; Mustard

Tricarpellary: A condition when the pistil is composed of three carpels.

Polycarpellary: A condition when the pistil is composed of many carpels. Eg; Rose.

Position of ovary

Superior:

An ovary is said to be superior only when its base lies above the insertion of other floral parts. Example; Mustard.

Inferior:

In epigynous flower, the ovary is borne below the attachment of all other floral parts and adnate to them. Example: Coriandrum

Semi-inferior:

The intermediate condition between superior and inferior. Example; pea

Locules or Chambers of ovary

Unilocular: Ovary with one chamber. Eg; pea

Bilocular: Two ovarian chambers. Eg; Petunia

Trilocular: Three ovarian chambers. Eg; Asphodelus

Tetralocular: Four ovarian chambers. Eg; Ocimum

Pentalocular: Five ovarian chambers. Eg; shoe flower

Multilocular: Many ovarian loculi. Eg: Althaea

Aestivation and Placentation

Mode of an arrangement of sepals or petals in the bud is known as aestivation. The placenta is the tissue through which ovules remain attached to the ovary wall and get nutrition