Sterculia tragacantha Lindl.

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

Type

Type: Sierra Leone, cult. England, Bot. Reg. 16, t. 1353 (1830)

Morphology General Habit

Tree 3–24 m tall.

Morphology Bole

Bole cylindrical, sometimes with fluted buttresses.

Morphology General Bark

Bark rough, grey or greyish brown, often deeply fissured; slash pale pink or pale orange, quickly becoming deep orange, exudate clear.

Morphology Branches

Flora districts: Ultimate branchlets rough and grey, 5–10 mm thick, the apex rusty tomentose

Morphology Leaves

Leaf-blade elliptic-oblong or slightly obovate, (6.5–)11–21(–30) cm long, (4.7–)6.5–13(–16) cm wide, apex rounded to acuminate, base truncate, rounded, or subcordate, texture papery or leathery, glabrous, sometimes glossy above, tomentose (sometimes tomentellous in shade or on sucker growth) with red-brown 5–6-armed stellate hairs beneath.

Morphology Leaves Petiole

Petiole terete, slightly swollen at base and tip, (2.5–)5–7.5 cm long, 1–2 mm wide, tomentellous with pale brown stellate hairs; stipules caducous

Morphology Reproductive morphology Inflorescences

Inflorescences borne with the leaves, 2–10 per stem, each inflorescence 10–14(–22) cm long, 2.5–5(–8) cm wide, 2–3 mm thick at the base, with 20–25(–30) branches; pedicels 1–4.5 mm long

Morphology Reproductive morphology Flowers

Flowers with perianth campanulate, rose-pink, pinkish or brownish purple, rarely green tinged with red, 4–7(–8) mm long, 3–5 mm wide, divided into 5 acute lobes 3–4 mm long, 1.5 mm wide, cohering at the apex, margins reflexed, outer surface with a mixture of short, wide, flaccid, ± appressed, colourless hairs and fine, pale brown stellate hairs; inner surface glabrous apart from the extreme base and the lobes which densely covered in long, stout pointed, patent white or purple hairs

Morphology Reproductive morphology Fruits

Fruit with 3–5 follicles, follicles ellipsoid, 5.7–10 cm long, 2.5 cm wide, dehiscing flat, then 3.6–8.9 cm long, 4–8 cm wide, rostrum rather short, blunt, 3–5(–10) mm long, stipe stout, (0.5–)1(–2) cm long, pericarp thick, woody, 2–3 mm thick, outer surface red, then rusty brown, tomentellous, inner surface yellow-brown, stiffly and thickly tomentose.

Morphology Reproductive morphology Seeds

Seeds glossy black, ellipsoid, 10–13(–18) mm long, 7–9(–12) mm wide, hilum white, terminal, elliptic, 1–2 mm long, with a small, globose, orange aril 0.5–1 mm wide on a short margin; seeds sessile, leaving a white scar on the pericarp wall

Figures

Fig 1/3, 10, p 6

Ecology

Swamp and riverine forest; 750–1700 m

Conservation

This species is here assessed as “Least Concern” in view of its large geographic range. It is a fast-growing pioneer species.

Note

This plant has been reported, presumably on account of its specific epithet, to be a source of gum tragacanth. However, that production is derived only from species of Astragalus (Leguminosae). Whilst the gum from Sterculia tragacantha may resemble that of gum tragacanth as Lindley (Bot. Reg. 16: t.1353 (1830)) has mentioned, no reference has been found to its use as a substitute. Sterculia tragacantha is closely related to S. schliebenii and S. dawei, q.v. for diagnostic characters.

Distribution

Flora districts: T4 Range: Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Benin, Nigeria, Cameroon, Equatorial Guinea, Central African Republic, Congo-Kinshasa, Rwanda, Angola, Zambia

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/136111481/136111483

Conservation

LC - least concern

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

Morphology General Habit

Large tree 15 m. tall or more, with smooth greyish bark and stiff rugose branchlets.

Morphology Leaves

Leaves collected towards the ends of the branches; lamina up to 20 × 12 cm., leathery, entire, broadly oblong, obovate-oblong, or ovate-oblong, apex obtuse or abruptly acuminate, base rounded or slightly cordate, penninerved, thinly pubescent or glabrescent above, more or less ferruginously tomentose beneath; petiole up to 5 cm. long.

Morphology Reproductive morphology Flowers

Flowers reddish, in harshly pubescent panicles c. 12 cm. long, clustered at the ends of the branches. Female flower: ovary ovoid, tomentose, with a ring of vestigial anthers at its base, on a glabrous gynophore up to 1 mm. long; style c. 1 mm. long, tomentose. Male flower: stamens numerous, in a capitate globose cluster on a glabrous androphore c. 2 mm. long surrounded by a ring of hairs at its base.

Morphology Reproductive morphology Flowers Calyx

Calyx campanulate, divided to about half-way into 4–6 narrowly oblong lobes which are coherent at their tips, pubescent outside and on the lobes within.

sex Male

Male flower: stamens numerous, in a capitate globose cluster on a glabrous androphore c. 2 mm. long surrounded by a ring of hairs at its base.

sex Female

Female flower: ovary ovoid, tomentose, with a ring of vestigial anthers at its base, on a glabrous gynophore up to 1 mm. long; style c. 1 mm. long, tomentose.

Morphology Reproductive morphology Fruits

Follicles c. 5 cm. long, ellipsoid with an acute apiculus, ferruginously tomentose outside and inside.

Morphology Reproductive morphology Seeds

Seeds c. 1·6 × 1·2 cm., oblong-ellipsoid; testa black; aril small and yellow.