Solanum mauritianum Scop.

Flora Zambesiaca. Vol. 8, Part 4. Solanaceae. Gonçalves AE. 2005

Type

Type: t. 8 of Scop., loc. cit. (1788), proposed by K. Roe in loc. cit. (1972), as iconolectotype, based probably on a plant cultivated in the Hortus Botanicus Ticinensis, Pavia (northern Italy), raised from seed originating on Mauritius obtained from a French source.

Morphology General

Large shrub or small tree to 4.5(5) m high, evergreen, foetid, unarmed; hairs stellate, sessile to long stalked, sometimes bearing a long central ray, and also a few simple, multicellular hairs, loose and floccose on new growth; tiny glandular hairs also present

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary c.  1 mm in diameter, subglobose, tomentose.

Morphology Reproductive morphology Flowers Gynoecium Style

Style 5–6 mm long, exceeding the stamens, ± straight, stellate-pubescent on the lower half to two-thirds

Note

Chromosome number: 2n=24 Common name: "Bug Tree" or "Wild Tobacco Tree"

Ecology

Stream-banks and gardens; up to 1675 m.

Distribution

ZAM W, ZIM C, ZIM E, MOZ M Originally from Argentina and southern Brazil (fide Symon in tom. cit.: 97 (1981)) or native to Uruguay (fide K. Roe in tom. cit. (1972)) or to tropical Asia (fide Henderson & Anderson, loc. cit. (1966)), now widespread throughout the tropics, long-introd Zambia Zimbabwe Mozambique

Morphology General Habit

Large shrub or small tree to 4.5(5) m high, evergreen, foetid, unarmed; hairs stellate, sessile to long stalked, sometimes bearing a long central ray, and also a few simple, multicellular hairs, loose and floccose on new growth; tiny glandular hairs also present.

Morphology Branches

Branches thickly covered with white felty hairs, subglabrous with age. Branches thickly covered with white felty hairs, subglabrous with age

Morphology Leaves

Leaves solitary; petiole 1–5.5 cm long, usually with 1–2 sessile, obliquely ovate-falcate, rounded, auricle-like, leafy, discolorous pseudostipules 1.3–4 × 0.9–2.5 cm at the base; lamina membranous or chartaceous, 4.5–29.5 × 1.5–13 cm, elliptic to ovate-lanceolate, sometimes ± oblong, base rounded to cuneate, unequally decurrent into the petiole, apex rather obtuse, usually long-acuminate, entire or sub-undulate, velvety pubescent above, distinctly paler, whitish felty with denser tomentum beneath. Leaves solitary; petiole 1–5.5 cm long, usually with 1–2 sessile, obliquely ovate-falcate, rounded, auricle-like, leafy, discolorous pseudostipules 1. 3–4 × 0.9–2.5 cm at the base; lamina membranous or chartaceous, 4.5–29.5 × 1. 5–13 cm, elliptic to ovate-lanceolate, sometimes ± oblong, base rounded to cuneate, unequally decurrent into the petiole, apex rather obtuse, usually long-acuminate, entire or sub-undulate, velvety pubescent above, distinctly paler, whitish felty with denser tomentum beneath

Morphology Reproductive morphology Inflorescences

Cymes terminal, becoming lateral, stout, dichotomously branched, corymbiform or ± paniculiform, 6.5–12 cm across, ± condensed, many-flowered; peduncle 8–18 cm long, thick, densely felty pubescent; pedicels 2–5 mm long. Cymes terminal, becoming lateral, stout, dichotomously branched, corymbiform or ± paniculiform, 6.5–12 cm across, ± condensed, many-flowered; peduncle 8–18 cm long, thick, densely felty pubescent; pedicels 2–5 mm long

Morphology Reproductive morphology Flowers Calyx

Calyx 5–7 mm long, slightly accrescent, deeply divided, densely felty-pubescent to floccose-tomentose; tube campanulate; lobes 2–4.5 × 2–3 mm, ovate-triangular to ovate-lanceolate or oblong-elliptic, acute or obtuse; in fruit enlarged to 6 × 4 mm. Calyx 5–7 mm long, slightly accrescent, deeply divided, densely felty-pubescent to floccose-tomentose; tube campanulate; lobes 2–4.5 × 2–3 mm, ovate-triangular to ovate-lanceolate or oblong-elliptic, acute or obtuse; in fruit enlarged to 6 × 4 mm

Morphology Reproductive morphology Flowers Corolla

Corolla blue to purple or mauve with a pale “star” at the base, stelliform or saucer-shaped, 12–18 mm across, tomentose outside but less densely than the calyx; lobes 4–6 × 3–5.5 mm, ovate to triangular or lanceolate, ± acute. Corolla blue to purple or mauve with a pale “star” at the base, stelliform or saucer-shaped, 12–18 mm across, tomentose outside but less densely than the calyx; lobes 4–6 × 3–5.5 mm, ovate to triangular or lanceolate, ± acute

Morphology Reproductive morphology Flowers Androecium Stamens

Stamen filaments 0.5–1 mm long; anthers 2.5–3 mm long, narrowly ellipsoid, emarginate at both ends. Stamen filaments 0.5–1 mm long; anthers 2.5–3 mm long, narrowly ellipsoid, emarginate at both ends

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary c. 1 mm in diameter, subglobose, tomentose; style 5–6 mm long, exceeding the stamens, ± straight, stellate-pubescent on the lower half to two-thirds.

Morphology Reproductive morphology Fruits

Fruit dull yellowish when ripe, sub-shining, 9–12 mm in diameter, ± globose, densely stellate-pubescent or tomentose, becoming subglabrous with age, poisonous, with 2 sub-apical, irregularly flattened sclerotic granules. Fruit dull yellowish when ripe, sub-shining, 9–12 mm in diameter, ± globose, densely stellate-pubescent or tomentose, becoming subglabrous with age, poisonous, with 2 sub-apical, irregularly flattened sclerotic granules

Morphology Reproductive morphology Seeds

Seeds pale yellow to golden-brown, 2–2.2 × 1.5–1.8 mm, reniform, lenticular or ovate in outline, minutely reticulate. Seeds pale yellow to golden-brown, 2–2.2 × 1. 5–1. 8 mm, reniform, lenticular or ovate in outline, minutely reticulate

Cytology

Chromosome number: 2n=24.

Ecology

Habitat according IUCN Habitats Classification: forest and woodland, savanna, shrubland, native grassland, wetlands (inland), artificial - terrestrial.

Solanaceae, Jennifer M Edmonds. Oliganthes, Melongena & Monodolichopus, Maria S. Vorontsova & Sandra Knapp. Flora of Tropical East Africa. 2012

Type

Type: cultivated in Hortus Botanicus Ticinensis, Pavia from seed probably originating in Mauritius; type specimen unknown, t. 8, Scopoli (1788) designated as a lectotype by Roe (1972)

Morphology General

Shrub to 3 m or small tree to 7 m, evergreen, foetid; branches erect, yellowishgreen and velvety through dense tomentose/flocculose pubescence with mostly stellate hairs, either sessile or long, multiseriate-stalked (sometimes with a long central ray), mixed with some uniseriate simple hairs and small four-celled glands

Morphology Leaves

Leaves solitary to alternate, coriaceous, dark green above, whitish- to yellowish-green below, usually lanceolate, 19–34+ × 6–9 cm, bases cuneate and decurrent, margins entire, apices acute to acuminate; pubescent with predominantly sessile stellate hairs above, tomentose/flocculose below with predominently stalked stellate hairs, especially dense on lower midribs and veins; petioles 2.5–4.5 cm long, subtended by two small sessile ovate auricular pseudo-stipules, 1–3.5 × 0.9–1.8 cm

Morphology Reproductive morphology Inflorescences

Inflorescences terminal becoming lateral and axillary, dichotomously forked, many-flowered erect compound corymbs 14–25 × 7–14 cm, usually > 100-flowered; peduncles 10–18 cm long, thick; pedicels erect, 3–4 mm long in flower, 4–5 mm long in fruit, articulated; axes densely tomentose/flocculose

Morphology Reproductive morphology Flowers Calyx

Calyx cupulate, 4–6.5 mm long, yellowish-green and densely stellate-tomentose, glabrescent internally; lobes broadly ovate to broadly triangular, sometimes unequal, 2–4 × 1.5–2.5 mm, obtuse to acute, adherent in fruit and 2.5–5 × 1.5–3.5 mm

Morphology Reproductive morphology Flowers Corolla

Corolla flowers purple to lilac with pale basal star, stellate to pentagonal, 1.4–2.3 cm diameter; tube ± 1.5 mm long; lobes broadly ovate to triangular, 3.5–6.5 × 2.5–6 mm, acute, stellate-tomentose externally but less so than calyx, glabrous internally, margins sometimes inrolled, laterally reflexed exposing anthers after anthesis. Stamens equal to subequal; filaments free for 1–1.2 mm, glabrous; anthers yellow to yellow-orange, 2–3 × 0.9–1.2 mm, free

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary bilocular, 1–2 × 1.7–2 mm, densely pubescent; style straight to geniculate, exserted to 4 mm, 5.5–7 × 0.3–0.5 mm, stellate-pubescent at least in lower part; stigma clavate, 0.6–1.5 × 0.4–0.9 mm

Morphology Reproductive morphology Fruits

Berries yellow to yellowish-green, globose, with coriaceous pericarp softening with maturity, to 10 mm diameter, stellate-scabrid and glabrescent, probably shed with pedicels leaving scarring on inflorescence branches

Morphology Reproductive morphology Seeds

Seeds usually 100–150 or more per berry, yellow to yellowish-orange, orbicular, ovoid, spherical or discoid, 1.8–2 × 1.5–1.8 mm, foveolate; up to two globular sclerotic granules 0.8 mm diameter present.

Ecology

Escape from cultivated land, especially along forest paths and -margins, river banks and in dry river beds; 1150–2800 m

Note

This species is a highly successful pantropical weed now enjoying widespread distribution thoughout the tropics, largely due to the attraction of its succulent berries to birds causing rapid dispersal. Roe (1972) suggested that the dispersal of this and related species from their native South America to Africa coincided either accidentally or purposely with old Portugese and Spanish trade routes begun during the early- to mid- sixteenth century. Roe also noted that S. mauritianum is a successful coloniser of open and disturbed ground in a variety of habitats, and that it can also reproduce by adventitous shoots arising from shallow roots to form large colonies of plants. Jaeger & Hepper (Review of the genus Solanum in Africa, in D’Arcy (ed.), Solanaceae – Biology and Systematics: 48 (1986)) reported that S. mauritianum is the most notable of all the non-native Solanums introduced into Africa, now growing in western, central and eastern parts, and that is particularly widespread and troublesome in South Africa where it is thought to be the host plant for the larval stage of the Natal fruit-fly ( Pterandrus rosa). It is often known as the Wild Tobacco- or Bug- tree and is reportedly poisonous to pigs and cattle in Australia. In South Africa, Watt & Breyer-Brantwijk (1962) cited early reports of fruits of the synonymous S. auriculatum causing fatalities in humans in the Natal area as well as cattle poisoning, though birds eat the seeds without apparent ill effect. These authors also reported allergic skin reactions when the plants were handled together with various medicinal uses of this synonymous species. These included the treatment of Manioc poisoning by leaf juice application; leaf decoctions as a lotion for haemaerrhoid treatment, and the use of seeds mixed with coconut oil as an ointment to alleviate rheumatism. It is cultivated in New Zealand as a rootstock for the tree tomato ( Solanum betaceum – see page 104) Sendtner (1846) placed S. mauritianum in synonomy with S. auriculatum although the latter had been described one year later.

Distribution

Range: A troublesome weed in many parts of Australia, and often cultivated in Europe Range: Mauritius, Madagascar, Mascarenes Range: Native to southeastern Brazil, Uruguay and NE Argentina, now widespread and often naturalised throughout the tropics: Sierra Leone, ?Nigeria, Cameroon, Rwanda, Angola, Zambia, Mozambique, Zimbabwe and South Africa Range: Naturalised in the Atlantic Islands including Madeira and the Azores Range: Adventive in India, Nepal and Sri Lanka Flora districts: U4 K3 K4

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