Urena lobata L., Sp. Pl. 692 (1753)

Latin for 'lobed', referring to the leaves.

Urena americana L. f.
Urena grandiflora DC.
Urena lobata var. americana (L. f.) Gurke
Urena lobata var. trilobata (Vell.) Gurke
Urena reticulata Cav.
Urena trilobata Vell.

Subshrublike herbs, erect, to 1 m tall. Branchlets stellate tomentose. Stipules filiform, ca. 2 mm, caducous; petiole 1-4 cm, gray-white stellate; leaf blades on proximal part of stem nearly orbicular, 4-5 by 5-6 cm, base rounded or nearly cordate, margin serrate, apex 3-lobed, blades on middle part of stem ovate, 5-7 by 3-6.5 cm, those on distal part of stem oblong to lanceolate, 4-7 by 1.5-3 cm, abaxially gray stellate puberulent, adaxially puberulent. Flowers solitary or slightly aggregated, axillary. Pedicel ca. 3 mm, woolly. Epicalyx lobes connate for ca. 1/3 length, ca. 6 mm, puberulent. Calyx cup-shaped, lobes 5, slightly shorter than bracteoles, stellate puberulent, caducous. Corolla reddish, ca. 15 mm in diam.; petals 5, obovate, ca. 1.5 cm, abaxially stellate puberulent. Staminal column ca. 15 mm, glabrous. Style branches 10, hirsute. Fruit flattened globose, ca. 1 cm in diam.; mericarps stellate puberulent and spiny with hooked spines.

Grasslands, scrub, roadsides; up to 2200 m elevation. Readily invades disturbed areas, especially poorly managed pastures, scarified and eroded areas, and perennial crop plantations but is much less of a problem in annual crops. The species does not compete well in tallgrass swards and brushlands and does not grow under forest canopies. It grows on a wide variety of soils of varying fertility derived from most parent materials. It tolerates salt spray and a moderate amount of salt in the soil but does not grow in saturated soils.

Urena has long been used for its fibre in Brazil, but it has been slow in achieving importance as a cultivated fibre crop. The plantsĄŻ stalks are cut by hand, above the woody plant base. After the stalks are subjected to a retting operation, the fibres are removed by hand. Urena fibre is lustrous and creamy white or pale yellow in colour. The fibre strands are about 1 metre (3.3 feet) long. Urena fibre is fine, soft, and flexible and is readily dyed. Used much like jute, which it resembles in appearance and strength, urena is made into cordage, burlap (hessian), sacking fabrics, and carpeting materials and is often blended with jute or other fibres.

Pan-tropical, but originally probably from Asia.

Local names
China: Di tao hua.
English: Ceasar weed.