Dicotyledons of Ranunculaceae

 

Ranunculaceae (Buttercup Family)

Systematic position:

Polypetalae, Thalamiflorae, Ranales.

Field recognition:

Herbs, leaves often divided or palmately compound with sheathing leaf bases,stamens numerous and spirally arranged,carpels numerous, distinct,spirally arranged,unilocular.

Selected Indian genera:

Ranunculus, Aconitum, Actaea,Anemone,Caltha.

Size,distribution and general information:

Represented by about 50 genera and 1900 species,distributed in the temperate regions of the Northern Hemisphere.The common genera of which over 150 or more species have so far been reported, include Ranunculas, Aconitum, Anemone.Some species occur in Arctic and Alpine zones.Plants of this family flower mainly during winters in our country.

Description of the family:

General Habit-Generally annual or perennial herbs,rarely shrubs or vines,perennials perennate by means of rhizome,some species areaquatic herbs.

Root-Tap root as well as adventitious roots,tuberous roots of Aconitum,Paeonia and Ranunculus store food, swell and form tuber –like structures.

Stem-Aerial as well as underground,herbaceous,woody,climbing,branched.

Leaves-Usually basal and cauline,often palmately divided with sheathing leaf bases ,usually exstipulate,but stipulate in Caltha,Ranunculus,mostly alternate opposite,simple,aquatic species  of Ranunculas show heterophylly.

Inflorescence-Variously formed,solitary to paniculate,racemes or cymes,a single terminal flower is produced in Anemone and Eranthis,but more often a cymose branching is seen.

Flower-Bracteate or ebracteate,bracteolate or ebracteolate,bisexual or unisexual in some species of Thalictrum,usually actinomorphic but zygomorphic in Delphinium and Aconitum,hypogynos.

Delphinium

Calyx-3 to many   sepals,polysepalous,valvate or imbricate,sepals are petaloid in Aconitum.

Corolla-5 petals,polypetalous,nectariferous glands present,sometimes petals are many or absent,posterior petals are spurred.

Androecium-Stamens 5 to many,free,spirally arranged,anthers 2-celled,adnate,extrorse and longitudinally dehiscent,sometimes stamnodes are present.

Gynoecium-Numerous,free carpels with either one basal ovule or seval anatropous ovules showing marginal placentation,ovary superior,unilocular,style 1,stigma 1.

Fruits and seeds-Etaerio of follicles,etaerio of achenes,berry either apsule,seeds minute embryo and oily endosperm.

Floral formula:
 

Economic importance:

•    Ranunculaceae are important as ornamental and as drug plants.Its has showy flower and are grown as ornamentals in our gardens.

•     Aconitum napellus roots the source of aconite,used as a nerve sedative.

•     Actaea spicata roots used as a nerve sedative. 

•     Anemone pulsatilla is the source of the homeopathic drug ‘Pulsatilla’ used to cure nervous disorders in women during menstrual periods.

•    Clematis triloba leaves are used to cure snake bites.

•    Nigella sativa seeds are used as common condiment as well as in the treatment of cough, asthma and fever.