Solanum violaceum Ortega

Code

SOLVO

Growth form

Shrub

Biological cycle

Perennial

Habitat

Terrestrial

Global description

Solanum violaceum is a perennial thorny slender shrub, erect branched, which measures generally 1 to 1.5 m high. It is a plant completely covered with a gray tomentum of stellate hairs and has curved spines more or less dense on all its parts (stem, leaves, inflorescence). The stem is lignified at the base. The leaves are alternate, simple, ovate, margin typically sinuate to lobed. They are covered with a gray tomentum of stellate hairs and have few straight spines along the veins and petiole. The inflorescence is axillary and has 3 to 12 flowers. The stalk is thick. The flower has the shape of a star of purple color in the center of which a yellow cone tip emerge, the anthers of stamens are joined together. The fruit is a globular orange-red berry. It contains many sub circular small seeds.

General habit

Erect thorny perennial shrub, branched in the upper part, which measures 1 to 1.5 m high.
 
Underground system

Taproot system.
 
Stem

The stem is woody towards the base. It is cylindrical, solid, covered with gray pubescence of stellate hairs. It has bent more or less dense spines, 4 to 10 mm long and 1.5 to 7 mm wide, pale yellow in color.
 
Leaf

The leaves are simple and sub opposite, very unequal in size. The petiole measures 1.5 to 6 cm. It (upper surface) or curves (lower surface) along the midrib. The midrib is protruding below and is covered with stellate hairs and can carry a few straight spines. The leaf blade is elliptic to broadly oval, asymmetrically truncated base, obtuse, acute or acuminate apex. It measures 4 to 13 cm long and 2 to 12 cm wide. The margin that can be almost full, is usually more or less lobed (2-7 windings or 2-7 lobes on each side). It is ciliated. The leaf blade is covered on both sides with a gray pubescence of stellate hairs which gives it a greyish color. This pubescence is denser on the lower surface this is why this surface has a lighter color. The upper and lower face often have some straight spines.
 
Inflorescence

The inflorescence is a short lateral cyme, non axillary carried by a stalk of about 5 cm long. It is made of 3 to 12 flowers in distichous or scorpioide arrangement.

Flower

The flower has a pedicel (13 mm long) covered with stellate hairs. The calyx consists of 5 sepals fused in cup, finished with 5 serrated lobes of 2 to 3 mm long. It is covered with a stellate pubescence. The corolla is composed of five fused petals and spread in star of triangular lobes. It is purple. It measures 20 to 22 mm in diameter. It is smooth on the inside and covered with a stellate pubescence outside. The 5 stamens are shortly stalked. The anthers 5 to 6 mm long, yellow in color, are applied against each other, forming an upright cone. The ovary globular carries an elongated style that end in a lobed stigma.
 
Fruit

The fruit is a smooth globose berry, 8 to 13 mm in diameter, orange-red in colour, with a little accrescent calyx. It contains numerous seeds.
 
Seed

The seed is sub circular. It measures 2 to 3 mm in diameter.

Solanum violaceum flowers and fruits throughout the year.

Solanum violaceum is a perennial species. It is propagated by seed dispersed by fruit-eating birds and other animals.

Table of distinctive characters of some Solanum species
 

Species	Growth form	Spines	Hairyness	Leaf shape (simple)	Leaf size	Flower	Fruit	Fruit size
S. americanum	herbaceous	no	glabrous (weakly pubescent)	dentate	6 cm	white, 8 mm	black	7 mm
S. seaforthianum	liana	no	glabrous	deeply lobed	7 cm	blue-purple	red	10 mm
S. rugosum	shrub	no	brown yellowish felting	elliptical entire	20 cm	white yellowish		10 mm
S. mauritianum	shrub	no	tomentose withish pubescence	elliptical entire	20 cm	purple, 15 mm	yellow	12 cm
S. torvum	shrub	every where	greyish tomentum	more or less lobed	15 cm	white, 15 mm	yellow	12 mm
S. violaceum	shrub	yes	greyish tomentum	plus ou moins lobée	10 cm	purple, 20 mm	orangé	10 mm
S. stramoniifolium	arbuste	longues	glabrescent	lobed with strait spines	25 cm	white	yellow	20 mm
S. subinerme	arbuste	oui	stellate hairs	elliptical, few curved spines		violette	red orange

China: Species that are also found in forests, dry and bushy vegetation and in humid areas, along roadsides, between 100 and 2700 m altitude.
Comoros: ruderal species, observed at low and medium altitudes in the plots of vegetable crops, banana and cassava on sandy clay soil.
Madagascar: Solanum violaceum grows on fairly fertile soils of ferralitic humus type, or alluvial soils. It is a weed in fallows and at the edge of crops, canals or along paths in subhumid zone up to 1200 m altitude in sunny places. It is found in semi-intensive cassava, groundnut or maize cropping systems in the Middle East, Midwest, and Highlands regions.
Mauritius: Common species in the coastal areas of dry regions.
Reunion: Common species in the lower regions.

Toxicity

Fruits of Solanum violaceum contain 1.8% of steroidal alkaloids. The leaves and roots also contain steroidal alkaloid solanine, solanidine and solasodine.

Origin

Solanum violaceum is native to tropical Asia (China, India, Sri Lanka, Myanmar, Thailand, Cambodia, Laos, Vietnam, Indonesia and the Philippines).
 
Worldwide distribution

This species was introduced in Australia,, New Caledonia, Madagascar and in the Mascarene Islands (Mauritius, Reunion, Rodrigues).

 

Local harmfulness

Comoros: A weed rare in cultivation plots.
Madagascar: Solanum violaceum is an infrequent and not abundant weed species of lowlands or highlands in fairly fertile soils. It can be locally abundant on the edges of canals with rich but poorly managed alluvial soils.

Medicinal: In Bangladesh roots of Solanum violaceum are digestive, carminative, astringent for the intestine, heart tonic, expectorant and aphrodisiac; useful in asthma, cough, catarrh, colic, flatulence, worms, dysuria, toothache and fever. Crushed root is used for nasal sores. The leaf juice mixed with ginger juice is used to stop vomiting. Fruits are considered anthelmintic, laxative and digestive; useful in pruritus, leucoderma and asthma. The fruits are used against intestinal worms. The plant juice is used against the wounds between the toes. 

Local control

Comoros: Manual weeding.
Madagascar: Solanum violaceum is controlled by manual weeding in cassava or corn / fallow cropping systems.

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