FAMILY OF THE WEEK:PEDALIACEAE

Sesamum mulayanum







Martynia annua

FAMILY OF THE WEEK:PEDALIACEAE

In India it is represented by three genera and seven species occurring chiefly in south India. Martyniaceae is considered as a separate family by some.

Vegetative characters:

Annual or perennial herbs or rarely shrubs. Sometimes as in Martynia, the roots are tuberous. The leaves are opposite, exstipulate, simple entire lobed or divided.

Inflorescence and flowers:

The flowers are usually axillary solitary or in simple cyme or terminal raceme as in Martynia. At the base of the flower stalk characteristic glands are present which metamorphosed flowers are.

The flowers are perfect bisexual zygomorphic and hypogynous. The calyx is of usually five more or less united or distinct sepals. The corolla is gamopetalous, tubular-ventricose, limb obscurely bilabiate, five imbricate lobes. The stamens are usually foue, didynamous and epipetalous on the corolla tube. The fifth posterior stamen is represented by a small staminode. In Martynia there are only two fertile stamens and the remaining three are reduced to staminodes. The anthers are dithecous, introrsr and dehiscing longitudinally.

The gynoecium is bicarpellary and syncarpous with a superior ovary. The style is one and slender and the stigma is bilobed. A nectar secretins disc is present at the base of the ovary.

Fruits and the seeds:

The fruit is an indehiscent or dehiscent capsule often with a woody endocarp which is often horned or prickly. In Martynia the fruit bears two long curved horns.

Pollination and dispersal:

The flowers are often protandrous and are pollinated by insects which visit them for nectar.

The fruits are adapted for dispersal by large mammals. The fruits are armed with adhesive spines or hooks.

Examples:

Sesamum indicum

Sesamum mulayanum

Sesamum laciniatum

Martynia annua

Pedalium murex

FAMILY OF THE WEEK : PAPAVERACEAE

Argemone mexicana

California poppy (USA)

California poppy (USA)

FAMILY OF THE WEEK : PAPAVERACEAE

In India this family has 5 genera and about 20 species mostly confined to the Himalayas.

Vegetative characters:

Mostly perennial herbs with a milky or coloured latex.

The leaves are radical or alternate, exstipulate, simple and entire or more often lobed or divided.

Inflorescence and flowers:

The flowers are solitary at the end of main or lateral branches. Sometimes racemes or panicles. The flower buds are often nodding due to more rapid growth of one side of flower stalk.

The flowers are large showy, complete, hermaphrodite, actinomorphic, di-or tri merous and hypogynous.

The sepals are two or three(Argemone), free or united, imbricate and caduceus.

The petals are four to six, biseriate, imbricate and often rolled or crumpled in bud.

The androecium consists of numerous free stamens in several whorls; the filaments are slender; and the anthers are erect, dithecous, extrorse and opening lengthwise.

The gynoecium is of two to many carpels, and it is syncarpousThe ovary is superior and unilocular. The style is very short or absent and the stigmas are as many as carpels, radiating connate and opposite or alternating the placenta.

Fruits and seeds:

The fruit is a many seeded capsule opening by pores or by valves under the lobes of persistent stigmas. The seeds are small with a minute embryo and a copious fleshy fleshy or oily endosperm.

Pollination and seed dispersal:

Self and cross pollination.Flowers do not contain nectar and are visited by pollen seeking insects. The seeds are usually dispersed by wind or by birds, animals or human beings. The seeds of Papaver and Argemone are dispersed by adhesion to animals, carts or feet of humans.

Examples:

Papaver somniferum L: Opium poppy

Papaver rhoeas (Corn poppy)

Papaver nudicaule (Iceland poppy)

Papaver orientale (Oriental poppy)

Argemone mexicana

ORCHIDACEAE

Habenaria marginata

Aerides maculosum

Zeuxine strateumatica

FAMILY OF THE WEEK: ORCHIDACEAE

A large family of 735 genera and over 17000 species, cosmopolitan in distribution but abundant in tropics and rare in arctic regions. This is the second largest family of the Indian flora, with 128 genera and about 881 speciesoccuring in Himalayas western ghats.They are most abundant in eastern Himalayas.

Vegetative characters:

Perennial herbs, terrestrial, epiphytic or saprophytic. The tropical species are mostly epiphytes while those occurring in temperate zones are largely terrestrial.

They have fleshy roots, root stocks corms or bulbs.

Terrestrial forms are sympodial. The internodes are often swollen to store food.

The epiphytic forms are mostly sympodial or sometimes monopodial. They develop aerial roots which have an outer layer of water absorbing tissue, the velamen. Most epiphytic forma drop their leaves in dry season. They usually develop a fleshy pseudo –bulb every year. The saprophytic form don’t have green leaves and they grow on humus.

The leaves are alternate often distichous or rarely opposite. The leaves are often fleshy linear or ovate. They are sheathing at base and encircling the stem.

Inflorescence and flowers:

They are solitary or in racemes spikes or in panicles.

The flowers are often showy and beautifully coloured. They are bracteates, bisexual or rarely unisexual zygomorphic and epigynous. The perianth is in two trimerous whorls, the outer often calyx like and inner corolla like. The tepals are free or variously connate in each whorl. Outer tepals are alike. The two lateral tepals of the inner whorl are alike but the median tepal is very different in size, shape and the colour from the lateral tepals. It is bulbous,spurred,tubular,strap shaped or variously divided and contribute to the beauty of the flower. This modified tepal is called lip or labellum.

The most characteristic pattern of the orchid flower is gynandrium or coloumn which is a highly complex structure formed by the adnation of the stamens style and the stigma.

The androecium is usually represented by one or two sessile anthers.

The gynoecium is tricarpellary and syncarpouswith an inferior ovary.

Fruits and seeds:

The fruit is usually a capsule opening laterally by three to six hygroscopically sensitive valves. The seeds are large in number minute often fusiform and rarely winged.

Pollination and seed dispersal:

The flowers are adpted for insect pollination.The innumerable light seeds are suited to distribution by wind.

Examples:

Cypripedium

Catteleya

Habenaria

Vanda

Cymbidium

Dendrobium

Epidendrum

Orchis

Aeridis

Vanilla planifolia

OXALIDACEAE

Oxalis dehradunensis

FAMILY OF THE WEEK : OXALIDACEAE
The OXALIDACEAE contains 3 genera and 875 species mostly in tropical and subtropical region.In India there are 2 genera and about 12 species distributed mostly in Himalayas. Indian sorrel is a common example found throughout India.
Vegetative characters :
Perennial herbs. Plants often produce fleshy rhizomes or bulbous tubers. The leaves are alternate or radical(Oxalis), digitately (Oxalis) or pinnately(Biophytum) compound and exstipulate.
The leaflets are folded and bent downwards in bud at night. The leaves of many species of Biophytum are sensitive and the leaflets bend down when touched.
Inflorescence and flowers :
The flowers are solitary or subumbellate or racemose.They are bracteate, complete and hermaphrodite, actinomorphic, pentamerous and hypogynous. The calyx is of five imbricate and persistent sepals which are free or united. The corolla is composed of five shortly clawed, free or basally connate petals. The androecium is of 10 stamens in alternate whorls.They are obdiplostemonous. The filaments are connate at the base. The gynoecium is pentacarpellary and syncarpous with a superior five-locular ovary. The styles are five, free and persistent and the stigmas are capitate or shortly divided.
Fruits and seeds :
The fruit is loculicidal capsule. The seeds have a straight embryo enveloped by a fleshy copious endosperm. An explosive aril is often present on the seeds.
Pollination and seed dispersal :
The flowers are protandrous and the pollination is by insects. The seeds are shot off as the capsule opens.
Examples :
Oxalis corniculata
Oxalis pes-caprae,
Oxalis corymbosa
Oxalis latifolia
Oxalis dehradunensis
Biophytum sensitivum