Sterculia subviolacea K.Schum.

First published in H.G.A.Engler, Pflanzenw. Ost-Afrikas, C: 271 (1895)
This species is accepted
The native range of this species is Cameroon to W. Tanzania and Zambia. It is a tree and grows primarily in the wet tropical biome.

Descriptions

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]

Sterculiaceae, Martin Cheek & Laurence Dorr; Nesogordonia, Laurence Dorr, Lisa Barnett. Flora of Tropical East Africa. 2007

Type
Type: Tanzania, Mwanza District: E Uzinza [Usindscha], Stuhlmann 3549 (B†, holo.); Mwanza District: Geita, Carmichael 473 (K!, neo.; EA!, isoneo. fide Wild 1961)
Morphology General Habit
Evergreen tree 12–27 m tall.
Morphology Bole
Bole sometimes fluted or buttressed; ultimate branchlets 4–4.5 mm thick, pale greyish-brown, ± glabrous, drying with numerous fine longitudinal creases; bud-scales 4–6, oblong, acuminate, 3.5–4.5 mm long, 1–3 mm wide, caducous
Morphology Leaves
Leaf-blade elliptic to oblong or slightly obovate, 12–23 cm long, 7–14 cm wide, apex rounded, rarely obtuse or subacuminate, base rounded to truncate, rarely slightly subcordate, very leathery, glabrous and drying pale green above, completely covered by a greenish white layer of interlocking, individually inconspicuous fimbriate peltate scales beneath; midrib, secondary and tertiary veins prominent below, covered with a fragile waxy layer.
Morphology Leaves Petiole
Petiole terete, 15–40 mm long, 1.5–2.5 mm wide, sometimes swollen at base and tip, very sparsely stellate-hairy at first, soon becoming glabrous; stipules caducous.
Morphology Reproductive morphology Inflorescences
Inflorescence borne with leaves, 1–4 per stem from the highest leaf axil, 9–20 cm long, covered in long, woolly purplish-red stellate hairs, lowest branch 2–3.5 cm from the base, 2–5 cm long, bearing 4–7 partial peduncles, each (1–)3-flowered.
Morphology Reproductive morphology Inflorescences Bracts
Bracts caducous, 3.5–5 mm long, 1–2 mm wide,
Morphology General Indumentum
Indumentum as peduncle.
Morphology Reproductive morphology Flowers Pedicel
Pedicels 4–5 mm long
Morphology Reproductive morphology Flowers
Flowers reddish–purple; perianth campanulate, 5–7.5 mm long, 5–6.5 mm wide, divided halfway into 5 lobes initially joined at the tips Female flower with gynophore 0.5 mm long, with ± sessile, reduced stamens at the base of the globose, tomentose ovary Male flowers with androphore 1.5–1.8 mm long
sex Male
Male flowers with androphore 1.5–1.8 mm long
sex Female
Female flower with gynophore 0.5 mm long, with ± sessile, reduced stamens at the base of the globose, tomentose ovary
Morphology Reproductive morphology Fruits
Outer surface reddish brown with longitudinal wrinkles, subscabrid with appressed stellate hairs, inner surface softly tomentose, hairs brown. Fruits with undehisced follicles scarlet, 6.5–8 cm long, 2.5 cm wide; when dehisced becoming wider than long, wall 4–5 mm thick, rostrum 6–9 mm long, stipe 0.8–1.2 cm long
Morphology Reproductive morphology Seeds
Seeds not known, but without a peg-like stalk persisting on the fruit
Ecology
Gallery and swamp forest; 900–1500 m
Conservation
This species is here assessed as “Least Concern” in view of its large geographic range and because its habitat is ± undisturbed through most of its range, so far as is known.
Note
The white lower leaf surface and purplish, woolly hairy inflorescence are each highly characteristic for S. subviolacea amongst the species in East Africa with entire leaf-blades. Only seven specimens have been seen from East Africa. Fruiting collections with seeds are needed.
Distribution
Flora districts: T1 T4 Range: Cameroon, Congo-Kinshasa, Angola, Zambia
[FTEA]

Sterculiaceae, H. Wild. Flora Zambesiaca 1:2. 1961

Morphology General Habit
Massive tree up to 30 m. tall, with a buttressed bole.
Morphology Leaves
Leaves similar in shape and size to those of 5. tragacantha but deep green and glabrous above and very densely and closely appressed-whitish-stellate-tomentellous below.
Morphology Reproductive morphology Flowers
Flowers in axillary or terminal panicles c. 14 cm. long; branches of inflorescence violet-tomentose. Female flower: ovary ovoid, tomentose, with a ring of rudimentary stamens at its base, on a glabrous gynophore c. 0·5 mm. long; style c. 1 mm. long, tomentose; stigmas recurved. Male flower: stamens 8–10, in a capitate globose cluster on a glabrous androphore c. 1·5 mm. long.
Morphology Reproductive morphology Flowers Calyx
Calyx up to 8 mm. long, campanulate, divided to half-way or a little more into 5 oblong lobes somewhat coherent at their tips, stellate-tomentose outside with some larger purple hairs among the paler ones, pubescent inside with some longer purple simple hairs and some subsessile simple glandular hairs.
sex Male
Male flower: stamens 8–10, in a capitate globose cluster on a glabrous androphore c. 1·5 mm. long.
sex Female
Female flower: ovary ovoid, tomentose, with a ring of rudimentary stamens at its base, on a glabrous gynophore c. 0·5 mm. long; style c. 1 mm. long, tomentose; stigmas recurved.
Morphology Reproductive morphology Fruits
Follicles similar in size and shape to those of S.tragacantha.
Morphology Reproductive morphology Seeds
Seeds c. 1–4 cm. long, oblong-ellipsoid; testa black.
[FZ]

Uses

Use
None recorded
[FTEA]

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/
  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2025. 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 Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2025. 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