Study of Family Bignoniaceae

Systematic position/ Classifications:

Venation reticulate, 2 cotyledons                                        Class- Dicotyledons

Perianth with distinct petals & sepals, petals fused          Subclass- Gamopetalae

Flowers hypogynous, stamens equal to number of petals,

gynoecium superior, bicarpellary                                       Series- Bicarpellatae

Corolla zygomorphic, staminodes

present, ovules more than 4                                                            Order- Personales

                                                                                                Family- Bignoniaceae     

    

Distribution: Members of this family are distributed throughout the world mainly in tropics. There are 650 species from 120 genera.

Salient features:

Plants are mostly shrubs & trees. Tecomeria & Pandorea are lianas.

Leaves are opposite decussate, compound, terminal leaflet modified into tendril, exstipulate and pinnately compound.

Flowers are bisexual, Zygomorphic, hypogynous, bracteates, bracteolate and pentamerous.

Calyx- with 5 sepals, united, campanulate, lobed or bilabiate, valvate aestivation.

Corolla- with 5 petals, united, campanulate, imbricate aestivation, obliquely campanulate or infundibulliform, lobes 5, sometime bilabiate.

 Androecium- with 4 stamens, didynamous, 5^th epipetalous, posterior one is reduced to staminodes 2 (Catalpa). Anthers are dithecous, introrse dehiscing by longitudinal placentae.

Gynoecium- is bicarpellary, syncarpous, superior; style terminal; stigma forked, bifid numerous anatropous erect ovules attached to axile placenta.

Fruit- is a 2-valved septicidal or loculicidal capsule or berry. Seeds non-endospermic, flattened, winged, sometime comose in Chilopsis.

Note-

Floral formula:

Floral diagram:

Morphological peculiarities:

Plants arborescent (i.e. trees/shrubs).

Leaves compound.

Flowers Zygomorphic with bracts & bracteoles.

Presence of posterior Staminode.

Antherlobes divergent & seemingly one above the other.

Fruits capsule with winged seeds.

Economic importance & their uses-

Ornamental plants:

Spathodia campanulata (Pichkari)- A native to Tropical Africa.  

Jacaranda mimosifolia (Neel Mohar)- A native of Brazil & Argentina.

Bignonia-

Tecoma stans (Yellow Bell)- A native to Tropical South America.

Kigelia pinnata (Bramhadanda)- A native to Tropical Africa.

Millingtonia hortensis (Cork tree or Akashneem)-a native to S.E. Asia & Malesia.

Tabebuia argentia & T. rosea- A native to Paraguay

Wild plants-

Heterophragma quadriloculare (Varas)

Dolichandron falcata (Medshingi)

Oroxylum indicum (Tetu)

Pagenali longifolia

Radermachera xylocarpa

Sterospermum chelenoides (Padal)

Present status, affinities, phylogeny & inter-relationship of Bignoniaceae:

Bessey placed this family in Scrophulariales, the origin of which was traced from Polemoniales. Hallier included it in order-Tubiflorae and placed it near Pedaliaceae and Acanthaceae. Hurchinson put it under 53^rd Order Bignoniales. According to Hutchinson Bignoniales originated from Loganiales.