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Wednesday 29 October 2008

NYMPHACEAE


NelumboNeucifera(Lotus)

Water lilyViolet


Nymphea pubescens(Water lily)

FAMILY OF THE WEEK : NYMPHACEAE
The family is represented by 8 genera and about 90 species most abundant in tropics. In India there are 4 genera and 7 species occurring throughout India.
Vegetative characters :
They are perennial aquatic herbs with a creeping or erect sympodial rhizome. There is a scattered arrangement of vascular bundles.
The leaves are usually large, simple and long petioled, arising from the root stalk or from the slender floating stem (Cabomba). They are usually floating or sometimes emerged as in Nelumbo. often peltate.
Inflorescence and flowers :
The flowers are axillary, solitary, long peduncled, and float on the surface or raised much above the water(Nelumbo) or partially submerged. The flowers are large showy, often sweet scented, bisexual, actinomorphic, hypogynous or more or less epigynous and acyclic to cyclic.
The calyx and corolla are poorly differentiated. The calyx is composed of 3-5 sepals. The sepals are distinct and green or coloured and petioled.
The corolla is polypetalous with three to indefinite and variously coloured or white showy petals. In Nymphea numerous spirally arranged petals gradually pass into stamens.
The androecium is composed of three to indefinite distinct stamens. The gynoecium is of two to three to numeruos carpels. In Nelumboideae there are a large number of carpels which are embedded separately in round pits which are on the flat upper surface of of a swollen spongy and obconical receptacle.
Fruits and seeds :
In Cabomboideae the fruit is a closed indehiscent follicle with one to three pendulous seeds. In Nelumboideae the fruit is indehiscent one seeded nutlet. The seeds are with a large embryo and with no endo ro perisperm. In Nymphaeoideae the fruit is a spongy berry with numerous seeds and it dehisces by swelling of mucilage. The seeds have small embryo and endosperm and abundant perisperm.
Pollination and seed dispersal :
Bright and showy fragrant flowers favour pollination by insect, flies and small beetles.Seed dispersal is mostly by water. Somespecies of Nuphar, Brasenia, and Cabomba are dispersed by ducks which eat the pulp of these fruits greedily.
Examples :
Nelumbo nucifera (Lotus) Kamal Nymphaea nauchali(Indian red water Lily) Nymphaea stellata(Indian blue water Lily) Nymphaea alba (European white water Lily) Victoria amazonica(Royal water Lily)

Saturday 11 October 2008

MYRTACEAE


Syzigium cumini

Eucalyptus sp.

Callistemon


Psidium guajava (Guava,Amrood,Peru)


Syzygium (Jamun,Jambhul)

FAMILY OF THE WEEK :MYRTACEAE
A large family of 120 genera and 3375 species worldwide. In India there are 14 genera and 165 species occurring chiefly in Eastern India.
Vegetative characters :
Trees or shrubs with aromatic fragrance.
The vascular bundles in the stem are bicollateral and oil glands are present in young stem leaves and floral parts.The leaves are opposite or rarely alternate or crowded at the ends of branches, simple persistent, thick,mostly entire and exstipulate.
Inflorescence and flowers :
The flowers are axillary solitary(Psidium), in racemes (Barringtonia),in heads or spikes(Callistemon) or in cymes(Tristania).
The flowers are bracteate and often have two bracteoles at the base. They are hermaphrodite, actinomorphic,four or five merous, epigynous. The calyx is composed of four or five sepals. The corolla is of five petals. Mostly the stamens are numerous, free, or united into bundles opposite the petals. The gynoecium is two to several carpellary syncarpous and with an inferior ovary having as many locules as the number of carpels. The style is one smooth or bearded at the summit and the stigma is simple. The ovary is crowned by a fleshy disc.
Fruits and seeds :
The fruit is loculicidally or septicidally dehiscent or sometimes indehiscent woody or fibrous or a fleshy berry.
Pollination and seed dispersal :
The flowers are pollinated by insects which visit for nectar secreted by the fleshy disc crowning the ovary.Species like Callistemon are pollinated by birds.The dispersal of seeds takes place by wind or by birds and animals.
Examples :
Eucalyptus (Nilgiri)
Syzygium (Jamun,Jambhul)
Psidium guajava (Guava,Amrood,Peru)
Pimenta officinalis (Allspice)
Callistemon Myrtus communis.

MUSACEAE





FAMILY OF THE WEEK : MUSACEAE
A small family of two genera (Musa and Ensete) In India only one genus Musa with 10 species occurring in the Himalayas western ghats and Assam.
Vegetative characters :
They are perennial large to gigantic herbs attaining a height upto 15 meters. They persist by means of underground rhizome.
The aerial pseudo stem which is usually tall, stout and unbranched is formed by imbricate,sheathing and stiff bases of the leaves. A short conical axis is concealed at the base of the shaft and its growth is terminated by the inflorescence. The axillary shoots provide new growth.
The leaves are spirally arranged, large and oval or oblong with a stout midrib and numerous parallel veins extending to the margins.
Inflorescence and flowers :
The plant produces a single terminal inflorescence which springs from the rhizome and emerges at the top of the pseudo stem.The flowers are arranged collaterally in racemes and are protected by large brightly coloured spathe like bracts.Flowers are mostly unisexual and the plants are monoecious with male flowers in upper bracts and female within the lower bracts.
They are zygomorphic, trimerous and epigynous. The perianth is of six members in two whorls of three each.There are six stamens.The gynoecium is tricarpellary and syncarpous with an inferior ovary. The style is filioform and the stigma is three lobed.
Fruits and seeds:
The fruit is a fleshy berry which does not produce any seeds in cultivated form of Musa.
The seeds have a thick and hard testa.
Pollination and seed dispersal :
Insects pollinate the flowers who visit for the nectar. Sometimes also by nectar seeking birds.Seeds are dispersed by animals.
Examples:
Musa paradisiaca L. subsp. sapientum (Banana. Kela)
There are over 200 varities under cultivation.

Friday 3 October 2008

FAMILY OF THE WEEK : MIMOSEAE


Parkia biglandulosa

Albizzia procera (किनई )

Adenanthera pavonina

e saman

Acacia nilotica

Acacia auriculaeformis

Adenanthera pavonina

Albizzia lebbek

Mimosa hamata

Albizzia chinensis

Dichrostachys cinerea

FAMILY OF THE WEEK : MIMOSEAE
Bentham and Hooker divided the Leguminosae into three subfamilies : Papilionaceae,Caesalpinieae and mimoseae.Most of the recent taxonomist treat them as three distinct families.

MIMOSEAE : There are about 56 genera and2800 species widely distributed in the tropical and subtropical regions but they are abundant in southern hemisphere. In India this family is represented by 15 genera and 72 species mostly in tropical and subtropical Himalayas and western Peninsular India.

Vegetative characters :

They are mostly trees and shrubs and rarely herbs(Neptunia) or woody climbers, climbing with the help of leaf tendrils (Entada)

The stems of climbing species show anomalous growth in thickness and they become winged. Tannin sacs and gum passages are common in pith and medullary rays.

The leaves are usually alternat and bipinnate or rarely simply pinnate as in Inga. The stipules are present and in some species of Acacia they are modified into thorns. In many species of Australian acacia the leaves are represented by simple green phyllodes. The leaves of Mimosa and Neptunia are sensitive to touch and assume a sleep position.

Inflorescence and flowers:

The minute flowers are generally in dense globose headsbut sometimes they are spikate or racemose(Prosopis and some Acacias). In dicrostachys the spikes are dimorphic.

The flowers are actinomorphic, bisexual or rarely unisexual or polygamous, mostly pentamerous and hypogynous.

The calyx is composed of usually five sepals which are united into a short tube. the corolla is also usually of five petals.

The number and cohesion of stamens show much variation.Generally they are numerous. The Gynoecium is of single carpel. The ovary is superior and unilocular with usually several ovules along the ventral suture. The style and stigma are one.

Fruits and seeds :

The fruit is legume or indehiscent.In several species of Acacia the fruit is lomentum. It is constricted between the seeds and breaks into one seeded segments. The seeds are with scanty endosperm.

Pollination and seed dispersal :

The flowers are pollinated by insects which are attracted by long exerted and beautifully coloured stamens. The seeds are dispersed by wind, birds or animals.

Examples :

Mimosa pudica (Sensitive plant)Lajalu

Mimosa hamata

Acacia nilotica,(Babhul) Acacia melanoxylon, Acacia auriculaeformis, Acacia concinna, Acaciacatechu, Acacia ferruginea, Acacia leucophloea

Albizzia lebbek, Albizzia procera, Albizziaodoratissima,Albizzia amara, Albizzia chinensis,

Pithecolobium dulce

Dichrostachys cinerea(Sigamkathi)

Prosopis juliflora

Xylia xylocarpa
Adenanthera pavonina(Ratangunj)