BIGNONIACEAE (Trumpet Creeper Family)
shrubs, or lianas, sometimes with tendrils. Leaves opposite or whorled, lacking
stipules, simple or compound. Inflorescences various, axillary or terminal.
Flowers perfect, hypogynous, without subtending bracts. Calyces actinomorphic
or zygomorphic, splitting irregularly into 2 lobes or 5-lobed, the lobes
sometimes reduced to teeth or nearly absent. Corollas zygomorphic, 5-lobed,
sometimes appearing 2-lipped. Stamens 2 or 4, the filaments fused to the
corolla tube, the anther sacs often appearing relatively distinct from each
other and spreading, sometimes attached asymmetrically with one sac appearing
terminal and the other appearing somewhat lateral. Staminodes sometimes also
present, 1–3, particularly in some genera with only 2 functional
stamens. Pistil 1 per flower, of 2 fused carpels. Ovary superior, with 2
locules, the placentation usually axile. Style 1 per flower, the stigma 1, with
2 deep flaplike lobes. Ovules numerous. Fruits capsules, linear-elongate,
2-valved, longitudinally dehiscent. Seeds variously shaped, flattened, winged.
One hundred to 120 genera, about 800 species, cosmopolitan, but most diverse in
tropical and subtropical regions, especially northern South America.
In the tropics,
the Bignoniaceae are among the most important families of lianas. A number of
lianas, shrubs, and trees in several genera are cultivated as ornamentals,
especially in the southern states.
The genus Paulownia,
which was included in the Scrophulariaceae by Steyermark (1963) and in the Bignoniaceae
by Cronquist (1981, 1991), is segregated into its own family in the present
work, for reasons discussed in the treatment of Paulowniaceae. Paulownia
is distinguished most easily from the superficially similar Catalpa by
its bluish purple corollas and ovoid fruits.