Urena Dill. ex L.

Malvaceae, A. W. Exell. Flora Zambesiaca 1:2. 1961

Morphology General Habit

Suffrutices, usually stellate-pubescent.

Morphology Leaves

Leaves petiolate, subentire, 3–5-palmatilobed or sinuous along the margin, palmately 3–7-nerved, with a conspicuous gland near the base of the central nerve; stipules small, linear to setaceous, usually caducous.

Morphology Reproductive morphology Flowers

Flowers axillary, solitary or fasciculate or crowded towards the end of the branches.

Morphology Reproductive morphology Flowers Epicalyx

Epicalyx campanulate, deeply 5-lobed; bracts lanceolate, acute, striate towards the base.

Morphology Reproductive morphology Flowers Calyx

Calyx cupulate, deeply 5-fid; lobes ovate or ovate-lanceolate, 1-nerved and keeled.

Morphology Reproductive morphology Flowers Corolla

Petals rose-pink or mauve, stellate-pilose outside.

Morphology Reproductive morphology Flowers Androecium Stamens

Staminal tube equalling the petals, the lower portion dilated and united with the petals at the base; anthers subsessile.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary depressed-globose, hirtellous or glabrous, of 5 free 1-ovulate carpels; styles 10, reflexed; stigmas discoid, fimbriate at the apex.

Morphology Reproductive morphology Fruits

Fruit subglobose, of 5 mericarps ultimately separating from the torus; mericarps trigonous, obovoid, coriaceous, indehiscent, the convex back stellately hirsute and with glochidiate spines, the flat lateral surfaces striate.

Morphology Reproductive morphology Seeds

Seeds obovoid-trigonous or reniform, glabrous.

Malvaceae, Bernard Verdcourt & Geoffrey Mwachala. Pavonia, B Verdcourt; Kosteletzkya, OJ Blanchard Jr.; Gossypium, P Fryxell & B Verdcourt. Flora of Tropical East Africa. 2009

Morphology General Habit

Perennial or annual herbs or subshrubs with stellate indumentum

Morphology Leaves

Leaves petiolate, subentire to deeply palmately 3–7-lobed, toothed, with often both coarse and finer teeth, palmately 3–9-veined, with a conspicuous gland near base of midrib consisting of a slit ± 1.5 mm long with thickened edges, sometimes also present on veins immediately on either side; stipules linear or setaceous, eventually deciduous

Morphology Reproductive morphology Flowers

Flowers solitary, fasciculate or merging into terminal pseudoracemes at the ends of the branches

Morphology Reproductive morphology Flowers Epicalyx

Epicalyx 5-lobed, the lobes ± rigid, narrowly triangular or lanceolate.

Morphology Reproductive morphology Flowers Calyx

Calyx 5-lobed, the lobes ovate to ovate-lanceolate, keeled

Morphology Reproductive morphology Flowers Corolla

Corolla pink or mauve, mostly with dark centre or rarely white, the petals obovate, densely stellate-pilose outside

Morphology Reproductive morphology Flowers Androecium Stamens

Staminal tube equalling the petals

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary of 5 free 1-ovulate carpels.

Morphology Reproductive morphology Flowers Gynoecium Style

Styles 10, reflexed, with discoid stigmas

Morphology Reproductive morphology Fruits

Fruits depressed globose, of 5 indehiscent trigonous mericarps, stellate-pubescent and with dense glochidiate spines dorsally (except in endemic Australian species), striate on the flat contiguous lateral surfaces.

Note

Formerly usually treated as a single species but apart from the pantropical species U. lobata with numerous varieties there are certainly three other distinct species in Australia (Craven & Fryxell in Austral. Syst. Bot. 2: 455–460 (1989)). One of these and several Indian species were transferred to Pavonia by Hochreutiner in 1901 but the latter may also be better considered as Urena again. Urena and Pavonia are extremely close and the former is the earlier name. It appears there are 4–6 species of true Urena.

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution

A pantropical genus of approximately eight species, with a single species in New Guinea, Urena lobata L.

Morphology General Habit

Herbs and shrubs to 5 m tall

Morphology General Indumentum

Indumentum stellate-pubescent

Morphology Leaves Stipules

Stipules filiform, caducous

Morphology Reproductive morphology Flowers Nectaries

Extrafloral nectaries present, on leaf underside, often yellowish

Morphology Leaves

Leaves simple, usually 3–5-lobed, occasionally ovate, oblong or lanceolate, base rounded or cordate, margins irregularly crenate or serrate, venation palmate

Morphology Reproductive morphology Inflorescences

Inflorescences axillary or terminal, few-flowered fascicles or of solitary flowers, rarely racemose. Flowers bisexual, actinomorphic, 5-merous; epicalyx fused, 5-lobed, calyx 5-lobed; petals pink or purple; staminal column equalling or shorter than the petals, anthers present throughout; ovary superior

Morphology Reproductive morphology Fruits

Fruit a schizocarp with 5 mericarps, covered with barbed hairs (in New Guinea)

Morphology Reproductive morphology Seeds

Seeds 1 per mericarp, glabrous.

Ecology

Urena has been collected in New Guinea from open and secondary habitats including rain forest edges from elevations up to 1700 m.

Recognition

Urena can be recognised in New Guinea by the leaves with irregularly toothed margins, the staminal column which is shorter than the petals and the fruit which is a schizocarp covered with barbed hairs.