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Monday 29 December 2008

FAMILY OF THE WEEK: RUTACEAE


Murraya koenigii (Kadhilimb)


Murraya koenigii (Kadhilimb)


Murraya panniculata (Kunti)


Feronia limoni (Wood apple)

FAMILY OF THE WEEK: RUTACEAE

CITRUS FAMILY

Widely distributed in tropical and temperate regions especially in south Africa and Australia. In India it is rep[resented by 23 genera and over 80 species mostly in Himalayas and western Peninsular India.

Vegetative characters:

They are trees shrubs or rarely herbs. A characteristic feature of the family is the presence of pellucid glands filled with essential oils. The plants have spines as in Citrus and Aegle. The leaves are opposite or alternate and simple or compound. The stipules are absent. The leaves are mostly gland dotted.

Inflorescence and flowers:

The flowers are usually born in axillary or terminal cymes or panicles., sometimes they form racemes or they are axillary solitary or fascicled. The flowers are bracteate as well as bracteolate, usually hermaphrodite or sometimes unisexual and polygamous as in Zanthoxyllum, actinomorphic or sometimes zygomorphic as in Dictamnus, pentamerous, and hypogynous. A fleshy nectariferous disc is present between the stamens and the ovary.

The calyx is of four or fivr sepals which are free or more often show various degrees of connation. The corolla is composed of four or five free petals, which are valvate or imbricate in bud. The stamens are as many as or twice the petals or sometimes they are numerous as in Aegle and Citrus. The filaments are usually free. The anthers are dithecous, introrse and dehiscing longitudinally. The gynoecium is of two to five carpels which are completely united or sometimes the carpels are free towards the base and the ovary is deeply lobed. The styles are as many as carpels, free or variously united. The stigmas are terminal, entire or lobed.

Fruits and the seeds:

The fruit is a capsule or of free membranous ventrally dehiscing few seeded carpels or a drupe or a berry. The seeds may or may not contain endosperm and the embryo is straight or curvrd.

Pollination and dispersal:

The Rutaceae are adapted for insect pollination. The seeds are largely dispersed by animals and also by human agency.

Examples:

Citrus limon (Lemon)

Citrus medica (Citron)

Citrus aurantifolia (Bitter orange)

Citrus sinensis (Sweet orange)

Citrus reticulata (Loose skinned orange, Santra)

Citrus paradise (Grape fruit)

Citrus maxima( Chakotra)

Aegle marmelose (Bael)

Feronia limoni (Wood apple)

Feronia elephantum (Kavath)

Zanthoxylum

Murraya koenigii (Kadhilimb)

Murraya panniculata (Kunti)

Tuesday 23 December 2008

FAMILY OF THE WEEK: RUBIACEAE


Ixora


Anthocephalus cadamba

Anthocephalus cadamba


Mussaenda

Pavetta

FAMILY OF THE WEEK: RUBIACEAE

Rubiaceae is a large family. In India there are about 76 genera and 274 species occurring chiefly in the tropical and subtropical Eastern Himalayas extending up to 4600 meters and mountains of southern and Western India.

Vegetative characters:

The habit is chiefly woody and the family consists of mostly trees and shrubs.

The leaves are opposite decussate or sometimes whorled, simple entire and stipulate. The stipules show much variation in the form. They are frequently interpetiolar or intra petiolar. The stipules are often united. Sometimes as in Gardenia the four stipules are united into a conical cap which is thrown off as the bud opens. The bases of stipules are often glandular.

Inflorescence and flowers:

The inflorescence is basically a dichasial cyme and sometimes the small flowered cymes are aggregated into dense head as in Anthocephalus and Adina. In Morinda even the ovaries of the flowers in the head become fused. Rarely the flowers are solitary as in Gardenia and in Coffee one to three flowers stand in the axil of a leaf.

The flowers are actinomorphic or rarely slightly zygomorphic, bisexual tetra or pentamerous and epigynous.

The calyx is four or five lobed and the lobes are valvate. Sometimes as in Mussaenda one of the sepals in one or more flowers of an inflorescence becomes brightly coloured. The corolla is four or five fused petals and is salverform, rotate or funneliform. The petal lobes are valvate, twisted or imbricate in bud. The stamens are as many as the number of petals and they alternate with them. The anthers are dithecous introrse and opening lengthwise. The gynoecium is usually bicarpellary and syncarpous. The ovary is inferior and bilocular with axile placentation. The style is simple and the stigma is capitates or bilobed.

Fruits and the seeds:

The fruit is usually a septicidal or loculicidal capsule. Sometimes it is a berry(Coffee) or schizocarpic, separating into one seeded segments (Galium)

Pollination and dispersal:

The pollination is brought about by insects. Sticky fruits and persistent calyx limbs often favour their distribution by birds and animals. Sometimes the seeds are winged and are dispersed by wind.

Examples:

Coffee

Cinchona

Ixora coccinea

Gardenia

Mussaenda

Anthocaphalus cadamba (Kadamb)

Mitragyna parviflora (Kalam, Laghukadamb )

Adina cordifolia

Randia spinosa

Morinda

Pavetta crassicaulis

Tuesday 16 December 2008

FAMILY OF THE WEEK: ROSACEAE


Sorbaria tomentosa





Potentilla atrosanguina


Rosa webbiana


Spiraea canescens


Potentilla eriocarpa


Sibbaldia purpurea


Pear


Wild strawberry


Wild rose

FAMILY OF THE WEEK: ROSACEAE

There are over 25 genera and around 215 species in India mainly confined to temperate Himalayas ascending up to 6000 meters.

Vegetative characters:

The plants are herbs, shrubs or trees several species of Rose and Rubus have prickles. Sometimes, as in Prinsepia and Crataegus the shrubs are armed with sharp spines which are modified branches. Vegetative reproduction takes place in several ways.

The leaves are alternate and simple, pinnately or palmately compound. The stipules are usually present.

Inflorescence and flowers:

The flowers are rarely solitary or fascicled, but commonly they are arranged in various types of definite or indefinite inflorescences. The flowers are actinomorphic or sometimes strongly zygomorphic, bisexual or unisexual,polygamous, pentamerous, hypogynous, peri or epigynous. The calyx is of typically five basally connate sepals; the calyx tube is free or adnate to the ovary. The aestivation is imbricate or valvate. In some genera an epicalyx is also present. The corolla is of generally five free petals (there are numerous petals in cultivated species of Rosa) which are usually imbricate in bud. The number of stamens is variable from one to many. They are often in whorls. The filaments are distinct or sometimes monoadelphous. The anthers are dithecous and introrse. A cushion shaped or ringlike nectar secreting disc is present between the stamens and carpel. The gynoecium shows much variation. There are ten different tribes of gynoecial characters and type of fruits.

Seeds:

The seeds are usually without endosperm.

Pollination and dispersal:

In most Rosaceae the nectar is collected in the receptacular tube and easily licked by insects. The flowers are mostly protogynous and favour cross pollination.

The seeds are dispersed by animals and birds.

Examples:

Rosa multiflora (Rose)

Rosa damascene

Rosa indica

Rosa banksiae

Rosa centifolia

Pyrus mallus (Apple)

Pyrus communis (Pear)

Prunus persica (Peach)

Prunus domestica

Prunus institia (Plum)

Prunus armeniaca (Apricot)

Prunus amygdalous (Almond)

Fragaria chiloensis (Garden Strawberry)

Fragaria vesca L. (Alpine strawberry)

Spiraea

potentilla

Brambles

Cinquefoil

Monday 8 December 2008

FAMILY OF THE WEEK: RANUNCULACEAE




Clematis

FAMILY OF THE WEEK: RANUNCULACEAE

(BUTTERCUP FAMILY)

In India there are 20 genera and 154 species mostly confined to mountainous region.

Vegetative characters:

They are mainly annual or perennial herbs but some are climbers such as Clematis. Some are aquatic herbs. The perennial species usually develop rhizomes and tuberous roots. The vascular bundles in the stem of some genera are not arranged in a ring but are somewhat irregular, recalling the arrangement of monocots.

The leaves are radical or alternate or opposite as in Clematis. Stipules are absent but they often have sheathing bases. Generally they are simple and palmately lobed or divided but they are entire in Caltha, pinnately compound in Clematis and decompounds in Thalicrtum. Aquatic species show heterophylly with submerged leaves finely dissected.

Inflorescence and flowers:

The Inflorescence is variable. Most of the genera show typically determinate Inflorescence. The flowers are solitary terminal in Anemone and Nigella. They form long racemes in Delphinium and Acotinum and much branched panicles in Clematis and Thalictrum. The flowers are generally bisexual, mostly actinomorphic. The flower parts are arranged spirally on an elongated receptacle. The sepals are 5-8, distinct, imbricate or valvate, usually deciduous. The petals are usually five free symmetrical or irregular. The stamens are many polyandrous and spirally arranged. The anthers are adnate dithecous, extrorse and dehiscing longitudinally. The gynoecium is usually of numerous free carpels arranged spirally on a distinct thalamus. The style and stigma are one.

Fruits and seeds:

The fruit is usually a group of few to many seeded follicles or a group of one seeded achenes. In Clematis the achenes have long persistent feathery styles. The seed has a copious endosperm and a minute straight embryo.

Pollination and dispersal:

The flowers are protandrous and are adapted for insect pollination. The dispersal is by wind in many species. Some are disseminated by animals and birds.

Examples:

Ranunculus (Buttercup)

Thalictrum (Meadow- rue)

Clematis ( Virgins- bower)

Anemone (Wind flower)

Delphinium (Larkspur)

Acotinum (Aconite)

Aquilegia (Columbine)

Nigella (Love-in-a-mist)

Nigella sativa (Black fennel,Kala jeera)

Caltha (Marsh Marigold)

Paeonia (Peony)

Adonis aestivalis

Monday 1 December 2008

FAMILY OF THE WEEK: POLYGONACEAE


Antigonon leptopus


Polygonum auriculata


Polygonum auriculata





FAMILY OF THE WEEK: POLYGONACEAE

In India the family is represented by 8 genera and 110 species occurring chiefly in Himalayas.

Vegetative characters:

Mostly herbs but few are shrubby or trees. Sometimes they are climbers such as Antigonon which climb with the help of tendrils terminating the racemes.

The stems are often with swollen nodes and in Cocoloba platyclada the stems and branches are flattened to form phylloclades. The epidermis often forms red pigment. The leaves are alternate, rarely opposite or whorled, simple and entire, toothed or lobed as in Rheum. The leaves are stipulate and the stipules are characteristic of the family. They are usually membranous and forming a complete sheath(ochrea) around the stem above the leaf base. Crystals of Calcium oxalate are often present in the epidermal cells.

Inflorescence and flowers:

The inflorescence is primarily a compound raceme whose branches are cymose. The flowers are small, bracteates, hermaphrodite, actinomorphic, cyclic or acyclic and hypogynous.

The calyx is of three to six, free or basally connate, often petalloid, white or red and persistent sepals which are often enlarged and membranous in fruit. The aestivation is imbricate. The petals are absent. The androecium is of 5-9 stamens. The filaments are free or united at the base. The anthers are dithecous and opening lengthwise.

An annular nectar secreting glandular disc is mostly present at the base of the ovary. Gynoecium is usually tricarpellary and syncarpous. The ovary is superior and unilocular. The style is two-four clefted. The stigmas are various.

Fruits and seeds:

The fruit is an angled achene usually enclosed in the calyx. The seeds have copious endosperm.

Pollination and seed dispersal:

The flowers are pollinated by wind or insects. The fruits are mostly distributed by wind as the persistent calyx forms a membranous wing. Sometimes they have wings which help distribution by birds or animals.

Examples:

Fagopyrum esculentum (Buckwheat,Kuttu)

Fagopyrum tataricum (Duckwheat)

Oxyria digyna

Rheum (Rhubarb)

Rumex acetosa (Garden sorrel)

Rumex acetosella (Sheep sorrel)

Polygonum (Knot weed)

Antigonon leptopus (Coral vine)