Characteristics of Acanthaceae | Distribution, Type, Inflorescence, Fruit, Floral formula

Characteristics of Acanthaceae | Distribution, Type, Inflorescence, Fruit, Floral formula

Characteristics of Acanthaceae are described below

Characteristics of Acanthaceae

• The family include256 genera & 2765 species mostly in tropical parts of the world

• In india, the family is represented by about 68 genera & 337 species occurring in the mountains of south & west India

Familiar plants include

Thunbergia spp.(clockwine), Justicia spp., Eranthemum nervosum,

Thunbergia spp.(clockwine), Justicia spp., Eranthemum nervosum,

• They are mostly annual or perennial herbs, under shrubs or shrubs & sometimes climbing(Thumbergia)

Stem of Acanthaceae

Stem: stems of climbing species show anomalous secondary growth.

• The cystoliths are commonly present in the epidermal cells of the leaf & stem


Leaves: Leaves are opposite & decussate, exstipulate(Adhatoda), 0r stipulate(Justicia)

• Simple & entire or rarely divided

exstipulate(Adhatoda), 0r stipulate(Justicia)

Inflorescence of Acanthaceae

• It is most commonly a dichasial cyme becoming monochasial at its ultimate branching

• The cymes are often condensed into axillary whorls(Hygrophila) or dense spikes(Adhatoda)

• The flowers are axillary solitary in Thunbergia


• Bracteate

• Bracteolate

• Pedicellate( sessile in Adhatoda),

• Perfect

• Hermaphrodite

• Zygomorphic

• Hypogynous

• In Thunbergia, & related genera the bracteoles are large and form involucre which incloses the flower


Cyalx of Acanthaceae

• It is usually five-partite

• Calyx segments are imbricate or valvate in bud

• In Thunbergia, the calyx is reduced to a narrow ring

• In Peristrophe the sepals are free


Corolla of Acanthaceae

Gamopetalous with a long or short tube

• The limb is sometimes almost equally five-lobed as in Thunbergia but usually it is 2 lipped

• In bi-lipped corolla, upper lip is usually erect & bifid and lower lip is horizontal & trifid

• Imbricate aestivation


Stamems of Acanthaceae

• They are often 4 & didynamous(frequently 2 in Justicia & Acanthus)

• Stamens are inserted in the corola tube & alternate with its lobes

•Filaments free

• Anthers : dithecous or monothecous, two anther cells are equal & lie at the same level or unequal in size & lower one is often spurred(Adhatoda)


Gynoecium of Acanthaceae

• Bicarpellary & syncarpous with a superior ovary situated on a  distinct nectariferous disc

• Style simple and Stigma bifid or simple

• Ovary contain one or more ovule in each locule

• Placentation is axile


Fruit of Acanthaceae

•Loculicidal capsule with 2 chambers or rarely drupe

• Seed : ovoid or compressed, non endospermic & with a large embryo

• Pollination: flowers are protandrous & entomophilous, mostly pollinated through bees




Floral formula of Acanthaceae :-

Floral formula of Acanthaceae

This is all about Characteristics of Acanthaceae. It topic Characteristics of Acanthaceae is very important for exams because of ray and disc flowers concept in t so don’t forget thus topic.

To know about Labiatae(Lamiaceae) Characteristics: Floral formula, Inflorescence | Mint family CLICK HERE

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