Sesbania herbacea (Mill.) McVaugh

Coffee-Weed

© SRTurner

Family - Fabaceae/Faboideae

Habit - Taprooted annual forb.

	Young plant.
© SRTurner

Stems - Erect, to 2 m, the base often somewhat swollen and spongy, glabrous, glaucous.

	Stem and nodes.
© SRTurner

Leaves - Alternate, pinnately compound, short-petiolate. Blades 8-30 cm long, with 30-70 leaflets. Leaflets 10-25 mm long, 2-6 mm wide, narrowly oblong to occasionally linear, entire, the surfaces glabrous.

	Pressed leaves.
© DETenaglia

	Leaflets adaxial.
© SRTurner

	Leaflets abaxial.
© SRTurner

Inflorescence - Loose axillary clusters 2-6 cm long with 2-7 flowers, the flower stalks 5-9 mm long.

	Inflorescence.
© SRTurner

Flowers - Calyx tubes 3-4 mm long, with short triangular lobes, bell shaped, glabrous, the lobes 1-2 mm long. Corollas papilionaceous, 11-15 mm long, glabrous, yellow. Stamens 10, with 9 filaments fused nearly to the tip.

	Flower.
© SRTurner

	Calyx.
© SRTurner

	Flower.
© SRTurner

	Flower.
© SRTurner

Fruits - Legumes, 10-20 cm long, 3-4 mm wide, quadrangular in cross section, with 20-40 seeds, these 3-4 mm long, oblong-ellipsoid.

	Plant in fruit.
© SRTurner

	Fruit.
© DETenaglia

	Seeds.
© SRTurner

Flowering - July - October.

Habitat - Bottomland forests, streambanks, oxbows, sloughs, crop fields, railroads, roadsides, open disturbed areas.

Origin - Native to North America.

Other information - In Missouri, this weedy yet attractive species has been found in three disjunct regions: in the Bootheel, near the far southwestern corner of the state, and mid-state along the major rivers. Missouri lies along the extreme northern extent of the plant's natural range, which occupies much of the southern portion of the country. The plant is readily identified by its tall stature, glabrous stems, large compound leaves, big yellow flowers, and long, drooping fruits. The leaves grow perpendicular to the stem giving the plant a distinctive appearance. Plants can grow to 3m tall or more. There is some resemblance to S. vesicaria, but that species is quite rare in Missouri and has smaller flowers and much different fruits.

The genus name Sesbania is a latinized version of the old name "Sesban" of Arabic origin. The species epithet herbacea derives from the Latin "herb(a)" meaning "grass, not woody." The taxonomy has been somewhat controversial. The plant has been used for erosion control. The seeds contain saponins and other toxic compounds which cause severe diarrhea and internal hemorrhaging.

Photographs taken off Hwy 29, Macon County, AL., 10-9-04 (DETenaglia); also Holly Ridge Conservation Area, Stoddard County, MO, 10-05-2011, Otter Slough Conservation Area, Stoddard County, MO, 8-19-2013, 9-11-2019, and 8-07-2022, and Dresser Island Conservation Area, St. Charles County, MO, 7-28-2020 (SRTurner).