Solanum seaforthianum Andrews

Code

SOLSE

Growth form

Vine

Biological cycle

Perennial

Habitat

Terrestrial

Global description

Solanum seaforthianum is a slender herbaceous or softly woody climber or creeper, to 7 m long or more. The stems are green, unarmed and mostly glabrous; a few glandular hairs are often present on the flowering branches. The leaves are alternate, simple, borne on short stalks, and variously lobed or dissected into unequal leaflets; these are bright green, thinly textured with entire margins and often undulate, sparsely pubescent or glabrous. Showy star-like flowers, blue to purple with yellow anthers, bloom in long drooping clusters. The fruits are spherical shiny red berries arranged in pendulous bunches. Seeds are numerous, compressed, reddish brown and shaggy pubescent.

Cotyledons

Cotyledons are elliptic to oblong, about 10-19 x 2.5-4.5 mm; venation is more obvious on the underside. Both the upper and lower surfaces are clothed in short hairs, margins ciliate.

First leaves

First leaves ovate, base rounded, both the upper and lower surfaces hairy, margins ciliate. Midrib raised on the upper surface. At the tenth leaf stage: leaf blade variable, margins entire to deeply lobed or the leaf could be interpreted as being pinnately compound with 7-9 leaflets. Midrib raised on the upper surface of the leaf blade. Underside of the leaf blade clothed in very small prostrate hairs. Crushed leaves emit an unpleasant odour.

General habit

Usually a slender vine, flowering and fruiting when quite small, but can grow to form a tree-top vine. Vine stem diameters to 3 cm recorded.

Underground system

Taproot.

Stem

The stem is green, unarmed and mostly glabrous; a few glandular hairs are often present on the flowering branches. It mesures 2 -7 m in lenght and up to 3 cm in diameter. There is no tendril.

Leaf

Leaves alternate, simple, more or less deeply lobed, so that they look like compound leaves. Petiole 1-2.5 cm; lamina c.7 × 5 cm, elliptic to obovate in outline, variously dissected, either deeply incised creating 3-9 lobes each up to 3.5-4.5 cm long and 1-2 cm wide, or appearing to be once-compound. Leaflets or lobes ± elliptic, variable in size, the terminal the largest and ± 3-lobed, glabrous to sparsely pubescent with short pale-coloured hairs along the margins and on veins of upper surface (short pale-coloured hairs just visible with a lens); base cuneate; apex acuminate; margin entire. Crushed leaves emit an unpleasant odour.

Inflorescence

Inflorescences are 10-50-flowered branched cymes, borne on a stalk (1-6 cm long) terminally at the end of the stems, but then becoming axillary as the plant keeps growing.

Flower

Pedicels 1-1.5 cm, thickened below the flower. Calyx very shallowly lobed (5 sepals, 1.5-2.5 mm long, fused at the base and with triangular tips); corolla of 5 petals 8-12 mm, blue, mauve or purple; anthers yellow; style 6.5-8 mm long. Flowers 10-15 mm in diameter.

Fruit

Globose berries, about 6-13 mm across, bright red.

Seeds

Seeds numerous, compressed, reddish-brown, patelliform, about 3-4 mm diam., testa +/- clothed in hairs. Embryo about 5-6 mm long, coiled in a flat spiral with the tips of the cotyledons in the centre.
 

Mayotte: Solanum sefortianum flowers and fruits all year round.
New Caledonia: Flowering of  Solanum seaforthianum takes place at the end of the rainy season followed by fruiting from June.
West Indies: Solanum seaforthianum flowers and fruits all year round but especially from November to June.

 

Solanum seaforthianum is a perennial creeper. It reproduces by seeds disseminated by certain frugivorous birds.

Table of distintive characters of some Solanum species
 

Species	Biology	Growth form	Spines	Hairyness	Leaf (shape)	Leaf (margin)	Leaf size	Flower size	Fruit	Fruit size
S. americanum	annual	herbaceous	no	glabrous (weakly pubescent)	oval	dentate	6 cm	white, 6-10 mm	shiny black	< 8 mm
S. nigrum	annual	herbaceous	no	pubescent	oval	dentate	6 cm	white 10-14 mm	dull black	> 8 mm
S. villosum	annual	herbaceous	no	weakly to strongly pubescent	elliptical oval	sinuose, dentate to weakly lobed	2-5 cm	white 5-12 mm	yellow orange	5-10 mm
S. seaforthianum	perennial	liana	no	glabrous	compound like	deeply lobed	7 cm	blue-purple 10-15 mm	red	6-13 mm
S. elaeagnifolium	vivacious	herbaceous	no	pubescent	narrowly elliptical	entire	2,5-10 cm	blue-purple 25-50 mm	yellow orange	10-15 mm
S. rugosum	perennial	tall shrub	no	brown yellowish felting	narrowly elliptical	entire	20 cm	dirty white 14-16 mm	light brown	8-13 mm
S. mauritianum	perennial	tall shrub	no	tomentose withish pubescence	wide elliptical	entire	10-30 cm	purple, 15 mm	yellow	10-15 mm
S. torvum	perennial	shrub	yes	greyish tomentum	elliptical oval	more or less lobed, spines on leaf	7-25cm	white, 15 mm	yellow orange	8-12 mm
S. violaceum	perennial	shrub	yes	greyish tomentum	elliptical oval	sinuate more or less lobed, spines on leaf	4-13 cm	purple, 20 mm	orange	10 mm
S. stramoniifolium	perennial	shrub	yes large	subglabrous	oval	lobed with strait spines	25 cm	white 15-25 mm	yellow	20 mm
S. subinerme	perennial	shrub	yes	stellate hairs	elliptical oval	ondulate, withour or with spines	15 cm	purple 25-40 mm	red orange	6-9 mm

Solanum seaforthianum is an ornamental vine cultivated in tropical and subtropical climates at altitudes ranging from sea level to 1300-1500 meters. Once naturalized, the species can grow in natural forests, natural meadows, forest edges, urban brush, banks, crops, orchards, pastures, roadsides, disturbed sites and areas of waste in dry and wet environments

Mauritius / Reunion: This species is cultivated in gardens, and naturalized in secondary forests and low altitudinal brushwood.
Mayotte:  Solanum seafortianum is an exotic species commonly naturalized in xerophilic vegetation. It is found in hedgerows on forest edges, field edges and paths. It can be found in xerophytic vegetation (islets) as well as in mesophilic or hygrophilic vegetation (mainland).
New Caledonia: Solanum seaforthianum colonizes secondary thickets, and may be present at the edge of dry forest (especially at Gouaro-Deva). It can adapt to many types of soils in rather humid areas and occasionally occurs in pastures. It grows on shrubs, bushes, which it uses as support. It also uses fences which can therefore constitute propagation corridors.
West Indies: Species found in hedgerows and inland forest edges. Sometimes cultivated in gardens.
 

 

Toxicity

Not consumed by cattle, Solanum seaforthianum and especially the seeds contain nitrates and solanines responsible for neuromuscular disorders.

Origin

Solanum seaforthianum is native to Central America.

 Worldwide distribution

This vine has been widely distributed as an ornamental plant in tropical areas. It is listed as an invasive plant and / or adventitious crop harmful crops in China, India, Taiwan, Namibia, East and Southern Africa, Cuba, Puerto Rico. It is present in the Pacific zone (Eastern Australia, Polynesia, New Caledonia), and considered invasive in Hawaii. In the Indian Ocean it is present in Comoros, Mayotte and Madagascar, naturalized in the secondary forests of Reunion and Mauritius.

Global harmfulness

Solanum seaforthianum is a very aggressive vine capable of invading natural forests, natural meadows, forest edges, urban brush, riverbanks, crops, pasturelands, roadsides, sites disturbed areas and waste areas. It has been included in the Global Invasive Species Database.

Local harmfulness

Mauritius: Not recorded in crops.
New Caledonia: Solanum seaforthianum was introduced in New Caledonia at the beginning of the 19th century, it is now less cultivated. It colonizes the secondary thickets, and may be present at the edge of dry forest (especially at Gouaro-Deva). Occasionally, it is found as a weed in pastureland.
Reunion: Not recorded in crops.
South Africa: Solanum seaforthianum is a noxious weed, prohibited plant that must be controlled; existing legislation: CARA 2002 – Category 1 Proposed legislation: NEMBA – Category 1b. A problem in Eastern Cape, KwaZulu-Natal, Mpumalanga, Gauteng and Limpopo. Invades riverine bush, Woodland and bush. Overtops and smothers other species. Poisonous. Indigenous birds could neglect the dispersal of indigenous plants as a consequence of their preference for the fruits of this alien species.

Ornemental: Solanum seaforthianum is cultivated as ornemental plant throughout the tropics and subtropics.

Local control

New Caledonia: Solanum seaforthianum colonizes the bushy pastures. It can then develop fairly quickly and it is advisable to manually eliminate the first appearances before fruiting. For stands already in place, spot treatment can be carried out on each foot if the support plant is to be protected. Spraying with a backpack will be done on the leaves during growth before flowering with a herbicide of type 2,4-D or triclopyr + 2,4-D.

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Solanum%2520seaforthianum