Definitions

lignosae

Bignoniaceae

The Bignoniaceae, or Trumpet Creeper Family, is a family of flowering plants comprising of about 650-750 species in 116-120 genera. Members of the family are mostly trees and shrubs, and more rarely lianas (Podranea and Macfadyena) and herbaceous plants in 116-120 genera. As shrubs, they are twine climbers or tendril climbers, and rarely root climbers.

Other common names for this family include jacaranda family, bignonia family or catalpa family. This family is commonly found as ornamental plants due to their large and often colorful flowers. Important members include the calabash tree (Crescentia cujete) and many genera cultivated in horticulture: Campsis, Catalpa, Jacaranda, Kigelia, Pandorea, Spathodea, and Tabebuia.

Distribution

The family, cosmopolitan, is present in both the Old World and the New World, with Catalpa the only genus common to both. Members are distributed mostly in the Tropics and subtropics, with the center of diversity in South America. A number of temperate species are found, mainly in North America and East Asia. 13 species in 8 genera (including 2 naturalised) are present in southern Africa. 12 genera and 35 species are present in China, 21 of which are endemic to China. In Australia, 10 genera and 17 species are present, only in the mainland states. In India, the family is represented by 15 genera and 40 species, which mostly occur in Western and Southern India and a few species in the Himalayas.

Description

Stem

In twining members, the stem is characterized by anomalous secondary thickening: in some segments xylem is added in much greater quantity than phloem and in other segments the reverse is observed.

Leaves

Members of this family commonly have pinnately compound or multiply compound leaves. Palmately compound leaves are rare. Simple leaves are also rare and, when observed, are often dissected in pinnatifid or palmatifid fashion. Leaves are typically in opposite but whorled (in Kigelia) or spiral arrangements are also found. Leaves are petiolate and exstipulate (but pseudostipules are present in the genus Markhamia). Domatia occur in at least 14 genera.

Flower

Flowers are bisexual, hypogynous and zygomorphic, either solitary or aggregated into racemes or cymes (dichasium or helicoid cyme). Inflorescence, when it occurs, might be axillary or terminal. Bracts and bractlets are present and sometimes deciduous.

The sepals are fused, forming a synsepalous calyx either entire or toothed in 5 lobes. The petals are equally fused into a sympetalous campanulate corolla that also has 5 lobes. These lobes are often clearly shorter than the tube. The corolla and calyx are distinct from each other. Sometimes, a 2-lipped (bilabiate) corolla is observed. In bud, the lobes are imbricate and more rarely valvate (such as in Pyrostegia).

The androecium is didynamous, i.e. there are 4 stamens occurring in 2 pairs of different lengths. The stamens are inserted epigynously and alternate with the corolla lobes. The anthers are often connivent but also separate from one another sometimes. One staminode may be present.

The gynoecium is stylate and median. It consists of one compound pistil with 2 carpels, a single style, and a superior ovary with typically 2 locules (more rarely 1 or 4), each bearing numerous axile ovules. An annular or cupular nectary disk usually occurs around the ovary base. Ovules are anatropous, with micropyles directed downward.

Fruit

The fruit is typically an elongated dehiscent capsule that opens loculicidally or septicidally. The fruit can sometimes be an indehiscent berry.

Seed and germination

The seeds, numerous, are usually winged and wind-dispersed but occasionally also comose and wingless. Arils are absent. Seeds do not have endosperms. There are 2 cotyledons. Germination is either phanerocotylar or cryptocotylar.

Reproduction

Pollination is either entomophilous (via insects), ornithophilous (via birds), or cheiropterophilous (via bats).

Use

Besides their use ase ornamental plants, some members also provide timber, such as the West Indian boxwood (Tabebuia), Catalpa, Oroxylum, Haplophragma, Spathodea, Meliosma, Stereospermum. The calabash tree's fruit is used in the Tropics as a water container. The fruit of the African sausage tree (Kigelia africana) is used in Africa as a laxative and for dysentery. The jacaranda is common as an avenue tree.

Biochemistry

Compounds detected from this family include arthroquinones (found in 4 genera), verbascosides (found in 8 genera), cornoside (found in Eccremocarpus), quercetin, ursolic acid and, more rarely, saponins.

Former and alternative classification

The following classification systems acknowledge family Bignoniaceae with the same circumscription as the APG II system classification: Cronquist's system, Dahlgren's classification, Reveal's classification, Stevens's classification, Takhtajan's classification and Thorne's classification.

Bentham and Hooker's classification placed this family under group Gamopetalae, series Bicarpellatae, order Personales. Engler and Prantl's classification placed the family under class Dicotyledoneae, subclass Sympetalae, order Tubiflorae. The Hutchinson system placed the family under phylum Angiospermae, subphylum Dicotyledones, division Lignosae, order Bignoniales.

The family was previously placed under the order Scrophulariales. Genera formerly placed under this family are Exarata, Gibsoniothamnus, Schlegelia and Synapsis, all of which now form family Schlegeliaceae.

References

  • Gentry, A. H. 1980. Flora Neotropica: Bignoniaceae - Part I (tribes Crescentieae and Tourrettieae. Flora Neotropica Monograph 25 (1): 1-150.
  • Gentry, A. H. 1992. Flora Neotropica: Bignoniaceae - Part II (tribe Tecomeae). Flora Neotropica Monograph 25 (2): 1-130.
  • Lohmann, L. G. 2006. Untangling the phylogeny of neotropical lianas (Bignonieae - Bignoniaceae). American Journal of Botany 93 (2): 304-318.
  • Bignoniaceae in L. Watson and M. J. Dallwitz (1992 onwards), The families of flowering plants.
  • iPlants for an updated checklist of the family.

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