Hagenia abyssinica (Bruce) J.F.Gmel.

Rosaceae, R. A. Graham. Flora of Tropical East Africa. 1960

Morphology General Habit

A rather slender tree up to 20 m. tall, with brown or reddish-brown, readily strip-peeling bark.

Morphology Twigs

Young twigs densely villous with yellow-brown soft ascending hairs 3–4 mm. long, with villous ring-scars of previous petiole-bases.

Morphology Leaves

Leaves petiolate, viscid, up to 40 cm. long:main leaflets commonly 6–8 on each side, sessile or almost so, narrowly oblong, commonly 12–15 × 3.5–5.2 cm., acuminate, basally rounded to subcordate, finely serrated and villous on the margins, with the primary nerves prominent beneath and the intervening veins reticulate, dark green, usually pubescent above, lighter green, densely villous with soft silvery hairs varying to glabrous beneath; rhachis usually with very small, ± orbicular secondary leaflets, 2–10 mm. long, between the main ones.

Morphology Leaves Petiole

Petioles 12–13 cm. long, winged due to the stipules being adnate for almost their whole length.

Morphology Reproductive morphology Inflorescences

Inflorescence a handsome, much-branched terminal drooping panicle 30–60 × 20–30 cm. at fullest maturity (the ♂ panicles usually relatively narrower), the branches villous, subtended by membranous and caducous leafy bracts; internodes ± zigzag; pedicels viscid; flowers subtended by 2(–3) broadly rounded bracts.

Morphology Reproductive morphology Flowers

Male flowers orange-buff to white, ± 7.5 mm. diameter at anthesis; calyx-tube 2–3 mm. long; outer calyx-lobes oblong or ovate to obovate, 1–1.5 × 0.5–0.75 mm., the inner lobes larger, 4–6 × 2.5–3 mm., reflexing and concave on the under side. Female flowers rather viscid, more red, up to 1.75 cm. in diameter; outer calyx-lobes unequal, oblong-linear varying to obovate, 7 × 3.75 to 9 × 5 mm., clearly veined; the inner lobes smaller, broadly ovate, 2.5 × 2 mm. Styles 1.25–1.5 mm. long; stigmas capitate; carpels asymmetrically ovoid, apically villous.

sex Male

Male flowers orange-buff to white, ± 7.5 mm. diameter at anthesis; calyx-tube 2–3 mm. long; outer calyx-lobes oblong or ovate to obovate, 1–1.5 × 0.5–0.75 mm., the inner lobes larger, 4–6 × 2.5–3 mm., reflexing and concave on the under side.

sex Female

Female flowers rather viscid, more red, up to 1.75 cm. in diameter; outer calyx-lobes unequal, oblong-linear varying to obovate, 7 × 3.75 to 9 × 5 mm., clearly veined; the inner lobes smaller, broadly ovate, 2.5 × 2 mm. Styles 1.25–1.5 mm. long; stigmas capitate; carpels asymmetrically ovoid, apically villous.

Figures

Fig. 5, p. 44.

Habitat

Upland rain-forests, often above the moist bamboo-thickets, and in upland evergreen bushland; 2400–3600 m.

Distribution

K3 K4 K5 T2 T3 T7 U1 U2 U3

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/117894181/153936071

Conservation

LC - least concern

Kew Species Profiles

General Description

An attractive African tree with soft leaves and hanging flower sprays, Hagenia abyssinica also has many uses. The wood is used for carving, carpentry, firewood and charcoal, and the flowers, roots and bark are used for medicinal purposes. An infusion of the flowers is used widely against tapeworms, and in Ethiopia this has been in use for so long that 'the master has taken his kosso' is a well-understood excuse meaning 'he cannot see you'.

Species Profile

Geography and distribution

Hagenia abyssinica is native to Eritrea, Ethiopia, Sudan, Uganda, Kenya, Congo-Kinshasa, Rwanda, Burundi, Tanzania, Zambia and Malawi.

It occurs in montane forests, especially in the upper forest region, at 2,300-3,300 m.

On most East African mountains, Hagenia abyssinica is common just below the tree-line (at about 3,000 metres above sea level), where it may form almost pure woodlands.

Description

Overview: A tree up to 25 m tall, often with a crooked bole (unbranched part of the trunk). The bark is reddish brown, fissured and peeling. Trees are either male or female and only rarely are flowers of both sexes found on the same tree.

Leaves: Pinnate (divided like a feather) with 11-16 hairy, toothed leaflets (and sometimes additional, minute leaflets in-between). Each leaf is held on a winged leaf-stalk, measuring 30-40 cm long in total.

Flowers: Male flowers are orange to brown or white with 12-20 stamens (male, pollen-bearing parts); female flowers are red. The flowers do not have petals, and the colour is mostly due to the bracts (modified leaves). Flowers are borne in large, many-flowered, hanging groups, 30-60 cm long and up to 30 cm across.

Fruits: Small and dry, remaining hidden within the dried flower parts.

Threats and conservation

Hagenia is widespread and often common where it occurs, and plant parts are harvested sustainably for many of their uses (rather than, for example, by cutting down the whole tree).

Highly valued by locals for its uses, Hagenia abyssinica is often left standing when forest is cleared.

It has been suggested that hagenia needs fires to regenerate, and it is true that it often occurs in even-aged stands.

Uses

An infusion made using dried and pounded female flowers has been used widely against tapeworms. This treatment has been used for centuries in Ethiopia, but its use is now in decline due to availability of reliable alternatives. Health organisations discourage the use of this infusion as the dosage cannot be controlled, and serious side-effects of over-dosage have been reported.

Roots of Hagenia are cooked with meat to produce a soup that is consumed as a treatment for general illness and malaria. The bark has been used in treatments for diarrhoea and stomach ache.

The dark red wood is used for furniture, flooring and carving, but is not durable. An attractive tree, hagenia is sometimes planted as an ornamental.

This species at Kew

Specimens of Hagenia abyssinica flowers, stem, bark and wood are held in Kew's Economic Botany Collection in the Sir Joseph Banks Building, where they are available to researchers by appointment.

Distribution

Ethiopia, Kenya, Malawi, Rwanda, Tanzania, Zambia

Ecology

Montane forests, forming dominant stands just above the moist forest/bamboo zone.

Conservation

Least Concern (LC) according to IUCN Red List criteria. Widespread and common.

Hazards

Side-effects resulting from consumption of infusions of hagenia flowers have been reported.