Rutaceae
Calodendrum

Calodendrum capense (L.f.) Thunb.

First published in Nov. Gen. Pl. 2: 43 (1782)
This species is accepted
The native range of this species is Kenya to S. Africa. It is a tree and grows primarily in the seasonally dry tropical biome.

Descriptions

Kew Species Profiles

General Description

Despite its common name, Cape chestnut is not closely related to chestnuts (Castanea species) or horse chestnuts (Aesculus species), but instead is a member of the citrus family (Rutaceae). It is not a typical citrus in appearance, as it is a large tree, with spectacular flowers, and the fruit does not look like those of its relatives (such as lemons, oranges and limes). It looks spectacular when in flower, as the large, pink flowers cover the whole of the crown (the leafy part of the tree).

Carl Thunberg (1743-1828), a Swedish physician and botanist who was a protégé of Carl Linnaeus (the father of modern taxonomy), saw this tree in South Africa in 1772. He was taken with it and gave it the generic name Calodendrum, which is derived from the Greek for 'beautiful tree'.

Species Profile
Geography and distribution

From the highlands of Ethiopia, the distribution of Cape chestnut follows the mountains of East Africa to the lowlands of the Cape. It is found in Ethiopia, Kenya, Uganda, Tanzania, Malawi, Zimbabwe and South Africa.

Description

Overview: A tree growing up to 7-20 m tall.

Leaves: Smooth and aromatic with scattered, translucent dots; about 14×8 cm and borne opposite each other on the stem.

Flowers: Pink and mauve flowers are produced in large, terminal sprays, often covering the whole canopy of the tree. Each flower has five spreading petals measuring up to 3.5×0.7 cm. The stamens (male, pollen-bearing parts) are as long as the petals.

Fruit: A round, warty capsule, splitting into five sections to release the ten black, angular seeds.

Threats and conservation

Cape chestnut has been assessed as Least Concern because it is widespread and can be locally common in drier upland forest as well as in forest margins and scrub in the south of its range.

Uses

The wood is hard and pale in colour. It is easily worked, bends well, and is used widely for furniture, flooring, tool handles and implements. The bark is widely used as an ingredient in cosmetics (some of which are used to dye the skin whitish), and the seed oil is used in soap-making. The seeds are readily eaten by birds and monkeys.

Millennium Seed Bank: Seed storage

The Millennium Seed Bank Partnership aims to save plant life worldwide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

A collection of Calodendrum capense seeds is held in Kew's Millennium Seed Bank based at Wakehurst in West Sussex.

See Kew's Seed Information Database for further information on Calodendrum capense  seeds

Cultivation

Cape chestnut is a popular ornamental in eastern and southern Africa and is easily grown from seed or cuttings. Young trees can grow a metre a year and transplant well.

This species at Kew

Specimens of Cape chestnut wood and bark 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, South Africa, Tanzania, Uganda
Ecology
Upland evergreen forest; lowlands to sea level in South Africa.
Conservation
Least Concern (LC) according to IUCN Red List criteria; widespread and locally common.
Hazards

None known.

[KSP]

Rutaceae, J.O. Kokwaro (University of Nairobi). Flora of Tropical East Africa. 1982

Morphology General Habit
Tree up to 20 m. high; young branches, leaves and inflorescences densely tomentose with simple, stellate and branched hairs, soon becoming glabrous.
Morphology Leaves
Leaf-lamina elliptic, 6–14(–18) cm. long, 3.5–8(–11) cm. broad, acute or slightly apiculate or rounded at the apex, cuneate to slightly cordate at the base; petiole 2–10 mm. long.
Morphology Reproductive morphology Inflorescences
Inflorescence up to 15 cm. long, with opposite cymose branches.
Morphology Reproductive morphology Flowers
Flowers mauve; bracteoles linear, 1.3–1.5 mm. long, caducous; pedicel up to 20 mm. long.
Morphology Reproductive morphology Flowers Calyx
Sepals ovate, 3–5 mm. long, 1.8 mm. broad, free or slightly connate at the base, minutely tomentose.
Morphology Reproductive morphology Flowers Corolla
Petals narrowly oblanceolate, 20–35 mm. long, 5–7 mm. broad, whitish or mauve, straight or somewhat recurved, tomentose with simple or branched hairs on the outside and simple hairs directed downwards inside.
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens as long as the petals; anthers 1.3–1.5 mm. long; staminodes longer than the petals, very narrowly oblanceolate, caudate, dotted with bright crimson glands.
Morphology Reproductive morphology Flowers Gynoecium Pistil
Gynophore 4–6 mm. long, glandular; ovary 2–3 mm. in diameter; style 15–20 mm. long.
Morphology Reproductive morphology Fruits
Fruit 5-lobed, strongly rugose-warty, ± 35 mm. in diameter, dehiscing from below with the 5 valves remaining attached to the top of a central column.
Morphology Reproductive morphology Seeds
Seeds black, semi-spherical to pyramid-like, 10–15 mm. in diameter.
Figures
Fig. 4/1–6, p. 12.
Habitat
Upland evergreen and riverine forests; 1200–2200 m.
Distribution
K1 K3 K4 K6 K7 T2 T5 T6 U2 U4
[FTEA]

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
[AERP]

Rutaceae, F. A. Mendoça. Flora Zambesiaca 2:1. 1963

Morphology General Habit
Tree up to 20 m. tall; young branches, leaves and inflorescences densely tomentose with mixed simple, stellate and branched hairs, soon becoming glabrous.
Morphology Leaves
Leaf-lamina 6–13 (18) × 3·5–7·5 (11) cm., elliptic to broadly elliptic, acute or slightly apiculate or rounded at the apex, cuneate or obtuse or slightly cordate at the base; petiole 2–10 mm. long.
Morphology Reproductive morphology Inflorescences
Inflorescence up to 15 cm. long, with opposite cymose branches.
Morphology Reproductive morphology Flowers
Flowers erect, mauve; bracteoles 1·3–1·5 mm. long, linear, caducous; pedicels up to 1·5 cm. long, stout.
Morphology Reproductive morphology Flowers Calyx
Sepals 3·2 × 1·8 mm., free or slightly united at the base, ovate, minutely tomentose with branched hairs on the outer surface and simple sericeous hairs within.
Morphology Reproductive morphology Flowers Corolla
Petals 3–3·5 × 0·6–0·7 cm., narrowly oblanceolate, straight or somewhat recurved, whitish or mauve, tomentose with simple or branched hairs on the outside and simple hairs directed downwards inside.
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens as long as the petals, inserted at the base of an annular disk; filaments filiform; anthers 1·3–1·5 mm. long, dorsifixed, sagittate; staminodes longer than the petals, very narrowly oblanceolate, caudate, dotted with bright crimson glands.
Morphology Reproductive morphology Flowers Gynophore
Gynophore 5 mm. long, glandular.
Morphology Reproductive morphology Flowers Gynoecium Pistil
Ovary 2–3 mm. in diam., globose, apiculate, papillose; style 18–20 mm. long; stigma capitate.
Morphology Reproductive morphology Fruits
Fruit a 5-lobed strongly rugose warty septicidal capsule 3·5 cm. in diam., dehiscing from below with the 5 valves remaining attached to the top of a central column.
[FZ]

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/146452303/146452305

Conservation
LC - least concern
[IUCN]

Uses

Use
Timber, ornamental, cosmetics.
[KSP]

Common Names

English
Cape Chestnut, Cape chestnut

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • Flora Zambesiaca

    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Herbarium Catalogue Specimens

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    • Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

  • IUCN Categories

    • IUCN Red List of Threatened Species
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Living Collection Database

    • Common Names from Plants and People Africa http://www.plantsandpeopleafrica.com/

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Species Profiles

    • Kew Species Profiles
    • http://creativecommons.org/licenses/by-nc-sa/3.0