Catalpa bignonioides Walter

Southern Catalpa

© SRTurner

Family - Bignoniaceae

Habit - Tree, to 15 m tall.

Stems - Woody, single trunk. Bark light brown, divided into thin, scaly plates on older trunks.

	Trunk.
© SRTurner

Leaves - Opposite or in whorls of 3, simple, long petiolate. Blades 8-22 cm long, ovate, entire or less commonly shallowly 3-lobed or 3-angled toward the base, narrowed or short-tapered at the tip, the bases truncate or cordate, the upper surface glabrous, the undersurface persistently pubescent with short, curly, unbranched to stellate hairs, especially along the veins.

	Leaf adaxial.
© SRTurner

	Lobed leaf.
© SRTurner

	Leaf abaxial.
© SRTurner

	Pressed leaf.
© DETenaglia

Inflorescence - Terminal panicle to 20 cm tall.

	Inflorescence.
© SRTurner

	Inflorescence.
© SRTurner

Flowers - Calyces 2-lobed, 9-12 mm long. Corollas zygomorphic, glabrous, 5-lobed, 2.5-4.0 cm long, the middle lobe of the lower lip not notched. Corolla white externally, patterned with purple and yellow or orange stripes and markings internally. Stamens 2. Staminodes 3, minute, fused to the corolla tube.

	Calyx.
© SRTurner

	Flower.
© SRTurner

	Corolla.
© SRTurner

	Stamens and style.
© SRTurner

Fruits - Elongate capsules 20-45 cm long, 0.6-1.0 cm in diameter, pendent, relatively thin-walled, the valves becoming flattened after dehiscence. Seeds with the body 12-16 mm long, 2.5-4.5 mm wide, the hairs of the tufts converging to a more or less pointed tip.

Flowering - May - June.

Habitat - Streambanks, roadsides, railroads, moist disturbed areas. Also cultivated.

Origin - Native to small portion of the southeastern U.S.

Lookalikes - Catalpa speciosa.

Other info. - This species can be difficult to tell from its close sibling C. speciosa, but typically has smaller flowers and fruits than the latter. Also, the corollas of C. bignonioides have a denser pattern of lines and spots in the throat, and the leaves have a strong unpleasant odor when crushed or bruised, whereas those of C. speciosa are less strongly and more pleasantly scented. Also, the lower flower petal in C. speciosa is broadly and shallowly notched, whereas the lower petal in C. bignonioides lacks this feature. Some botanists consider the two taxa synonymous.

Southern catalpa is planted as an ornamental and is less common in this state than C. speciosa. It is most commonly found in the Deep South, where it is native. In Missouri it is considered introduced.

Photographs taken at Riverfront Park, Washington, Franklin County, MO, 5-28-2020 (SRTurner).