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Monday, 23 February 2009

FAMILY OF THE WEEK: VITACEAE




Leea indica

FAMILY OF THE WEEK: VITACEAE

It is a small family with 12 genera and 700 species worldwide, distributed in tropics and warm temperate regions of the world. In India there are 8 genera and 95 species occurring in western peninsular India and in the Himalayas.

Vegetative characters:

They are mostly woody vines climbing by means of tendrils or adventitious roots. The tendrils are attached to the substratum by coiling or by adhesive discs. Species of Leea are small trees, shrubs or herbs. The stem is usually sympodial. The stem is angle compressed or cylindrical with numerous very large vessels, swollen or jointed nodes and watery juices. The leaves are alternate or the lower leaves are sometimes opposite, simple or palmately or rarely pinnately compound as in Leea. They are often pellucid punctuate and with deciduous stipules.

Inflorescence and flowers:

The numerous flowers are usually arranged in leaf opposed spikes, racemes, panicles or cymes. Occasionally the peduncles are flattened and expanded (Pterisanthes). Some peduncles are often transformed into tendrils or viscid discs which adhere to the substratum. The flowers are bracteates, hermaphrodite, rarely unisexual, actinomorphic, tetra or pentamerous and hypogynous. The calyx is small, four or five toothed or lobed or reduced to an inconspicuous ring. The corolla has four or five petals which are free or united. The petals generally fall when the flowers open. The androecium is of four or five stamens which are opposite the petals and are inserted at the base of the disc or between the lobes. The filaments are short, subulate and free or connate at the base (Leea). The anthers are free or connate, dithecous, introrse and open by the longitudinal slits. An annular or variously expanded nectariferous disc is present which is free or connate with the petals, stamens or ovary. The gynoecium is two to six carpellary and syncarpous with a superior and two to six locular ovary. The style is short slender and conical or absent and the stigma is capitates, discoid or sublobed.

Fruits and seeds:

The fruit is one to six chambered juicy berry with one or two seeds in each chamber. Seeds have a cartilaginous endosperm and a short basal embryo.

Pollination and dispersal:

The Vitaceae are insect pollinated.

Examples:

Vitis vinifera (Grape vine)

Leea indica (Dinda)

Leea macrophylla

Cissus adnata

Cissus woodrowii

Parthenocissus

Ampelopsis

Tuesday, 17 February 2009

FAMILY OF THE WEEK : VERBENACEAE


Tectona grandis(Teak)

Clerodendrum multiflorum


GmelinaArborea(shivan)


Clerodendrum serratum(Bharangi)


Petrea volubilis


Clerodendrum viscosum


Citharexylum quadrangulare


FAMILY OF THE WEEK : VERBENACEAE
A large family mostly distributed in tropical and subtropical regions. In India it is represented by 21 genera and 125 species occurring mostly in southern and western India and the tropical and subtropical Himalayas.
Vegetative characters:
Mostly annual or perennial herbs, sometimes shrubs or trees and rarely woody climbers(Petrea). Avicennia is a mangrove shrub or small tree.
The stem is often quadrangular and increases in thickness by formation of concentric rings of cambium. The leaves are usually opposite or whorled, exstipulate, simple or rarely pinnately or palmately compound.
Inflorescence and flowers :
The Inflorescence may be cymose, racemose or spicate. The cymes are often compound or panicled as in Tectona. The bracts and bracteoles are usually present.
The flowers are bisexual or sometimes polygamous by abor, more or less zygomorphic, usually pentamerous and hypogynous. The calyx is gamosepalous, persistent and usually five toothed or lobed. The corolla is gamopetalous, tubular and the tube often cylindric, limb bi lipped or unequally five lobed. The lobes are imbricate in bud. The stamens are four didynamous and epipetalous on the corolla tube. The anthers are dithecous, introrse and opening lengthwise. The gynoecium is bicarpellary and syncarpous. The ovary is superior with as many locules as the number of carpels. The stigma has as many lobes as the number of carpels.
Fruits and seeds :
The fruit is a drupe with one seeded pyrenes. The seeds have a straight embryo and are nonendospermic or with scanty endosperm.
Pollination and dispersal :
Mostly pollinated by bees and butterflies.The seeds are dispersed by birds and animals.
Examples :
Tectona grandis (Teak, Sag)
Premma bengalensis
Vitex altissima
Vitex negundo
(Nirgudi)
Gmelina arborea
(Shivan)
Lantana camara

Duranta repens

Petrea volubilis

Clerodendrum

Holmskioldia sanguinea
(Chinese hat plant)
Caryopteris incana.
Citharexylum quadrangulare

Wednesday, 11 February 2009

FAMILY OF THE WEEK: TILIACEAE


Grewia hirsuta



Grewia flavens

FAMILY OF THE WEEK: TILIACEAE

Chiefly distributed in tropical and temperate regions, in southeast Asia and Brazil. In India there are 14 genera and more than 110 species, found mostly in warmer parts.

Vegetative characters:
They are mostly trees or shrubs, sometimes herbs. The stems often have strong phloem fibre. The plants are usually covered with stellate hairs.
The leaves are usually alternate, often showing a distinct distichous arrangement, simple, entire or lobed. The blade is usually oblique with the larger side towards the branch. The stipules are free and often caducous and fall as the bud unfolds.

Inflorescence and flowers:
The flowers are usually arranged in cymose inflorescences which are axillary or terminal and few to many flowered. The flowers are complete, usually hermaphrodite, actinomorphic and hypogynous. The calyx is of mostly five, free or connate sepals which are valvate in bud. The corolla has as many petals as the sepals. the petals are free and show imbricate or valvate aestivation in bud. They are often glandular at the base.
The androecium has ten to numerous stamens, arising from a disc; distinct or basally connate in five bundles. The filaments are filiform and the anthers are dithecous, introrse and opening by a longitudinal slit or by an apical pore. In Grewia the stamens are raised by the development of an internode between the petals and the stamens.
The gynoecium is two to ten carpellary with a superior and sessile ovary.

Fruits and seeds:
The fruit is fleshy or dry and dehiscent or indehiscent. the seeds are endospermic with a straight embryo.

Pollination and dispersal:
The pollination is by insects. The fruits of Grewia are edible and the seed dispersal is by animals. In Triumfetta the fruits are adhesive and develop spines and thus attach to humans and animals.

Examples:

Corchorus capsularis (Jute)
Grewia
Triumfetta
Tilia

Wednesday, 4 February 2009

FAMILY OF THE WEEK: STERCULIACEAE


Sterculia foetida



Firminia colorata


Eriolaena quinquelocularis


Sterculia alata


Gauzuma


Dombeya


Pterospermum acerifolium

FAMILY OF THE WEEK: STERCULIACEAE

Family chiefly of tropics. There are 18 genera and more than 90 species mostly in tropical areas while some are in Himalayas.
Vegetative characters:
Mostly soft wooded trees or shrubs, sometimes herbs, rarely climbers. The younger parts are often stellate, tomentose. The bark is mucilaginous and the inner often fibrous. The leaves are alternate or rarely subopposite, simple, entire, palmately lobed or digitate(Sterculia). The petiole is often pulvinate. Stipules present usually caducous.
Inflorescence and flowers:
Inflorescences are axillary or sometimes terminal complex cymes. The flowers are hermaphrodite or unisexual or polygamous, actinomorphic, pentamerous and hypogynous. The calyx has five sepals, valvate more or less united, often coloured(Sterculia).Corolla has five petals. They are absent in Sterculia, free or adnate to the base of the staminal tube. They are deciduous or sometimes persistent(Dombeya). Androecium has few to many stamens which are free or often connate in tube. Gynoecium is 2-5 carpellary and syncarpous with a superior ovary, sessile or raised with androgynophore. The style is simple or lobed or rarely divided upto the base
Fruits and seeds:
Fruits are dry / fleshy, dehiscent/indehiscent. Seeds endo/nonendospermic with a straight or a curved embryo.
he seeds are numerous, compressed, discoid or subreniform, endospermic and with a curved or straight embryo.
Pollination and dispersal:
Pollination is by insects. Winged seeds of Dombeya and Pterospermum favor wind dipersal of seeds. It also takes place by animals and birds.
Examples:
Sterculia Pterospermum
Helicterus

Dombeya

Theobroma cacao
(Coco tree)
Cola acuminata
Gauzuma ulmifolia

Firminia colorata
Eriolaena quinquelocularis