Family: Solanaceae (Potato Family / Night shade family)

Family: Solanaceae (Potato Family / Night shade family)

Systematic Position

Diagnostic Features

·           Leaves alternate, exstipulate.

·           Flowers actinomorphic, pentamerous.

·           Calyx often persistence / accrescent.

·           Stamens 5, epipetalous, poricidal in dehiscence.

·           Carpels 2, ovary superior, 2 chambered, obliquely placed, falsely four chambered placenta swollen, ovule numerous.

·           Fruits berry or capsule, vascular bundles with both outer and inner phloem (Bicollateral vascular bundle).

General Characters

Distribution:

Family Solanaceae includes about 88 genera and about 2650 species, of these Solanum is the largest genus of the family with about 1500 species. Plants are worldwide in distribution but more abundant in South America.

Habit: Mostly annual herbs, shrubs, small trees (Solanum violaceum) lianas with prickles ( Solanum trilobatum), many with stellate trichomes; rarely vines (Lycium sinensis)

Root: Branched tap root system.

Stem: Herbaceous or woody; erect or twining, or creeping; sometimes modified into tubers (Solanum tuberosum) often with bicollateral vascular bundles.

Leaves: Alternate, simple, rarely pinnately compound(Solanum tuberosum and (Lycopersicon esculentum ) exstipulate, opposite or sub-opposite in upper part, unicostate reticulate venation.

Inflorescence: Generally axillary or terminal cymose (Solanum) or solitary flowers (Datura stramonium). Extra axillary scorpiod cyme called rhiphidium (Solanum nigrum) solitary and axillary (Datura and Nicotiana) umbellate cyme (Withania somnifera).

Flowers: Bracteate (Petunia), or ebracteate (Withania) pedicellate, bisexual, heterochlamydeous, actinomorphic or weakly zygomorphic due to oblique position of ovary pentamerous, hypogynous.

Calyx: Sepals 5, rarely 4 or 6, Synsepalous, valvale peristaent, often accrescent (enlarging to envelop the fruit) occasionally enclosing the fruit ( Physalis, Withania)

Corolla: Petals 5, sympetalous, rotate, tubular (Solanum) or bell- shaped (Atropa) or infundibuliform ( Petunia) usually alternate with sepals; rarely bilipped and zygomorphic (Schizanthus) usually valvate, sometimes convolute (Datura).

Androecium: Stamens 5, epipetalous, filaments usually unequal in length, stamens only 2 in Schizanthus(others 3 are reduced to staminode), 4 and didynamous in (Salpiglossis) Anthers dithecous, dehisce longitudinally or poricidal.

Gynoecium: Bicarpellary, syncarpous obliquely placed, ovary superior, bilocular but looks tetralocular due to the formation of false septa, numerous ovules in each locule on axile placentation.

Fruit: A capsule or berry. In Lycopersicon esculentum, Capsicum, the fruit is a berry and in species of Datura and Petunia, the fruit is a capsule.

Seed: Endospermous.

Botanical description of Datura metel

Habit: Large, erect and stout herb.

Root: Branched tap root system.

Stem: Stem is hollow, green and herbaceous with strong odour.

Leaf: Simple, alternate, petiolate, entire or deeply lobed, glabrous exstipulate showing unicostate reticulate venation.

Inflorescence: Solitary and axillary cyme.

Flower: Flowers are large, greenish white, bracteate, ebracteolate, pedicellate,

complete, heterochlamydeous, pentamerous, regular, actinomorphic, bisexual and hypogynous.

Calyx: Sepals 5, green synsepalous showing valvate aestivation. Calyx is mostly persistant, odd sepal is posterior in position.

Corolla: petals 5, greenish white, sympetalous, plicate (folded like a fan) showing twisted aestivation, funnel shaped with wide mouth and 10 lobed.

Androecium: Stamens 5, free from one another, epipetalous, alternipetalous and are inserted in the middle of the corolla tube. Anthers are basifixed, dithecous, with long filament, introse and longitudinally dehiscent.

Gynoecium: Ovary bicarpellary, syncarpous superior ovary, basically biloculear but tetralocular due to the formation of false septum. Carpels are obliquely placed and ovules on swollen axile placentation. Style simple long and filiform, stigma two lobed.

Fruit: Spinescent capsule opening by four apical valves with persistent calyx.

Seed: Endospermous.

Floral Formula: 

Botanical description of Solanum americanum

Habit: A small annual herb

Root: Branched tap root system.

Stem: Aerial, erect, green and herbaceous

Leaf: Simple, alternate but opposite in the floral region, petiolate, exstipulate ovate, entire or slightly lobed, acute unicostate reticulate venation.

Inflorescence: Extra-axillary (due to fusion of floral axis) scorpioid cyme called rhiphidium

Flower: Ebracteate, pedicellate, white, bisexual, actinomorphic, heterochlamydeous, pentamerous, hypogynous white.

Calyx: Sepals 5, synsepalous, green, persistent and showing valvate aestivation.

Corolla: petals 5, sympetalous, white, showing valvate aestivation.

Androecium: Stamens 5, apostamenous, epipetalous, filaments short, anthers conniving and forming an envelope around the style dithecous, basifixed with apical pores.

Gynoecium: Bicarpellary, syncarpous, superior, bilocular, many ovules in each locule on axile placentation, septum oblique, highly swollen placenta, style long and hairy at the base, stigma bifid.

Fruit: Berry

Floral Formula: 

Economic importance