There are numerous plant species on this planet and the major ones are angiosperms (flowering plants). In today’s article we are going to be studying about some families which belongs to the angiosperms group. The three families are – Fabaceae, Solanaceae and Liliaceae.
This family was also known as Papilionoideae. It belongs to the sub-family of family Leguminosae. It is distributed all over the world and is the largest sub-family out of the three families in Leguminosae. It is mostly found in temperate regions of northern and southern hemispheres. It includes of 375 genera.
Systematic position of the family Fabaceae:
- Class: Dicotyledons
- Sub-class: Polypetalae
- Series: Calyciflorae
- Order: Rosales
- Family: Leguminosae
- Sub-family: Pailionoideae or Fabaceae
Some common genera of this family – Pisum, Arachis, Lathyrus, Cicer, Phaseolus, Sesbania, Dalbergia, Melilotus, Vigna, etc..
Vegetative characters of Fabaceae Family:
◑ They are usually herbs and shrubs and rarely trees.
◑ They are sometimes hydrophytes and xerophytes.
◑ Most of the members yield pulses, hence they are cultivated in fields.
◑ Root system is tap root or branched.
◑ Nodules containing nitrogen fixing bacteria (Rhizobia) may be present on the root.
◑ Since these plants contain nitrogen fixing bacteria, they are used in green manuring (plant used as a fertilizer).
◑ The stem is erect or climbing. It climbs by tendrils.
◑ It is a branched structure.
◑ It is angular or cylindrical.
◑ It is herbaceous or woody.
◑ The leaves are arranged in alternate manner, opposite to each other or are whorled.
◑ It can be a compound leaf, digitate or pinnate (rare).
◑ Simple or stipulate stipules may occur at the base of the petiole.
◑ Secondary stipules may arise at the base of the individual leaflets.
Floral characters of Fabaceae Family:
● Infloresence – Racemose type.
◑ The flower is bisexual.
◑ It is zygomorphic (bilaterally synmmetrical) and pedicellate.
◑ It is a complete flower, perigynous (stamens and other floral parts at the same level as that of carpels) and papilionaceous (Flowers that resemble a butterfly).
◑ Sepals are five and gamosepalous (Sepals united).
◑ It is equal or unequal.
◑ These five sepals are lobbed or toothed or bi-labiate (2 upper and 3 lower may unite).
◑ Petals are five, polypetalous (many petals) and unequal.
◑ The corolla is formed of posterior petals (known as standard or vexillum), two lateral petals (known as wings or alae) and two anterior petals (known as keel or carina). The carina encloses stamens and pistil.
◑ Wide range of colours in petals.
◑ Venation is clearly visible (conspicuous).
◑ Stamens are ten and diadelphous (In bundles of two). They may be in combination of 5+5 or 9+1. They can also be monoadelphous (Single bundle). They are rarely free.
◑ Anther is dithecous (has two cells, thecae or compartments), bi-celled, dorsified, dehiscence (burting) takes place by longitudinal cuts.
◑ Carpel is one and free.
◑ Ovary is superior (above other floral parts), stalked (having a stalk) or sessile (fixed), unilocular and placed at the margin (marginal placentation).
◑ The style is single, bent, short and hairy.
◑ Stigma is simple.
◑ Fruits are in the form of seeds (legumes) or pod.
◑ The fruit shows splitting along the dorsal (back or upper side) and ventral (front or lower side) sutures.
◑ There is more than one seed.
◑ It is non-endospermic and usually flattened.
● Pollination – Entomophilous (insect pollination).
● Floral formula –・|・ ⚥ k (5), C 1+2+(2), A(9)+1, G1
Economic Importance of Fabaceae Family:
Many plants that belongs to this family are the sources of pulses like gram (Cicer arietinum), arhar (Cajanus cajan), sem (Lablab purpurea), soyabean (Glycine max), moong/mung (Vigna radiata), etc., dye like indigofera (Indigofera tinctoria), etc., fibres like sunhemp (Crotalaria juncea), etc., fodder like (Sesbania trifolium), etc. and medicines like mulaithi.
This family is also known as potato family. It is distributed in tropical regions – America and South America as well as in temperate regions. This family has 85 genera and 2200 species. The largest genus in this family is Solanum having 1500 species and other genera Lycium, Physalis and Nicotiana has 100 species each.
Systematic position of the family Solanaceae:
- Class: Dicotyledons
- Sub-class: Gamopetalae
- Series: Bicarpellate
- Order: Polemonials
- Family: Solanaceae
Vegetative characters of Solanaceae Family:
◑ These are mostly herbs and shrubs but rarely small trees.
◑ Small annual herb – Solanum nigrum.
◑ Large annual herb – Datura.
◑ Shrub – Cestrum nocturnum.
● Root – Tap root system or adventitious root.
◑ Stem is herbaceous and rarely woody.
◑ The stem is aerial, erect and branched.
◑ It is a solid, cylindrical and hollow structure.
◑ It is hairy or glabrous (smooth).
◑ In potato, the stem is modified underground.
◑ The arrangement of leaves are alternate or becomes opposite at or near the inflorescence. It is rarely whorled.
◑ Stipules – Exstipulate.
◑ Leaf margin – Smooth.
◑ The leaf is simple. It is rarely dissected or pinnate.
◑ Venation – Reticulate.
Floral characters of Solanaceae Family:
● Inflorescence – Cymose type of inflorescence, rarely helicoid.
◑ The flower is bisexual (hemaphrodite – having both male and female sexual organs) and complete.
◑ It is usually pedicellate.
◑ The flower is symmetrical (Actinomorphic).
◑ It is regular but sometimes slightly zygomorphic (bilaterally synmmetrical).
◑ It is hypogynous (Stamens and other floral parts situated below the carpels).
◑ They do not show the presence of bracts or bracteoles.
◑ Sepals are five and united (Gamosepalous).
◑ The calyx is persistent meaning it will be the same way even after the formation of the fruit.
◑ Petals are five and united (Gamopetalous).
◑ The corolla is funnel shaped.
◑ Corolla comes in various different shapes but it is rarely 2-lipped.
◑ Stamens are five, sometimes four and epipetalous.
◑ If the stamens are four they are didynamous (disposed in pairs of unequal length).
◑ Anthers are 2-celled (dithecous). Dehiscence (bursting) takes place through longitudinal slits or by apical (aerial) pore.
◑ Carpels are two (bicarpellary) and united (syncarpous).
◑ Ovary is superior and bilocular, though sometimes it may even become tetrolocular due to false septation. It is rarely 3-4 celled. It shows axile placentation.
◑ The carpels are placed obliquely (slanting) in the flower.
◑ Style is single.
◑ Stigma is bi-lobed and capitate.
◑ Placenta is swollen with many ovules.
● Fruit – Fruit is in the form of a berry or capsule.
◑ The seed is endospermic.
◑ It is smooth or pitted.
◑ A curved embryo is embedded (attached) in the endosperm.
● Pollination – Insect pollination (Entomophilous).
● Floral formula – ⊕ ⚥ K5, C(5), A5, G(2)
Economic Importance of Solanaceae Family:
Many plants that belongs to this family are sources of food like tomato (Lycopersicon esculentum), brinjal (Solanum melongena), potato (Solanum tuberosum), etc., spices like chillies (Capsicum frutescens), etc., medicines like belladonna (Atropa belladonna), ashwagandha, etc. and ornamental like Petunia.
This family is also known as Lily Family and has 240 genera and 4000 species. This family is cosmopolitan, meaning it is found everywhere in the world. It grows in temperate and sub-tropical regions. They are usually annual and perennial herbs, but sometimes can also be found in the form of soft woody shrubs.
In India, many genera are found, some of them are – Lilium, Aloe, Asparagus, Asphodelus, Glorisa, Smilax, Ruscus, etc.. Systematic position of the family Liliaceae:
- Class: Monocotyledons
- Series: Coronarieae
- Family: Liliaceae
Vegetative characters of Liliaceae Family:
◑ These plants are annual, biennial and perennial shrubs.
◑ Majority of the plants belonging to this family are xerophytic.
◑ Xerophytic plants have succulent and fleshy leaves. Eg, Aloe.
◑ The leaves are mostly basal.
◑ They are arranged in alternate or whorled form.
◑ The leaves are linear is shape.
◑ They show parallel venation.
◑ Stipules are exstipulate.
◑ They are simple, radical or cauline.
● Roots – The roots are adventitious and fibrous.
◑ In some species the stem is either underground, in the form of bulb, or rhizomes.
◑ Inflorescence grows on a special aerial stem called scape, eg., Asphodelus.
Floral characters of Liliaceae Family:
● Inflorescence – Solitary or Cymose type of inflorescence.
◑ The flower is bisexual, complete, regular, pedicellate and bracteate, though sometimes it can also be ebracteate.
◑ It is hypogynous (Stamens and other floral parts situated below the carpels) and trimerous (arranged in groups of three).
◑ It is actinomorphic (symmetrical).
● Perianth – Tepals (No difference between petals and sepals) are six in the combination of 3+3 which units to form a tube.
◑ Stamens are six in 3+3 combination, arranged in whorls. They are opposite to the perianth leaves. They can be free or adnate. The filaments are free or connate.
◑ Anther is dithecous (has two cells, thecae or compartments), introrse (turned inwards) and basifixed (attached by its base). Dehiscence of anther takes place by longitudinal slits and rarely by terminal pore.
◑ Carpels are three (tricarpellary) and fused (syncarpous).
◑ Ovary is superior, trilocular with many ovules arranged in two rows in each locules and shows axile placentation.
◑ There is only one style.
◑ Stigma is trilobed.
● Fruit – The fruit is either fleshy, in a capsule or a berry (Rare).
● Seed – The seed is endospermic or albuminous with straight embryo.
● Pollination – Insect pollination (Entomophilous).
● Floral formula – Br ⊕ ⚥ P(3+3) A(3+3) G(3)
Economic Importance of Liliaceae Family:
Many plants that belongs to this family are sources of ornamentals like tulip, Gloriosa, etc., medicine like Aloe, etc., vegetables like Asparagus, onion (Allium cepa), etc..