Vernonia galamensis
Encyclopedia
Vernonia galamensis is a plant in the sunflower family
, known for its use as an oilseed
. This species, often called ironweed, is the largest source of vernonia oil
, which is rich in a useful epoxy
fatty acid
called vernolic acid and is used to make plastics, rubbery coatings, and drying agents. Use of this oil as a replacement for traditional plasticizer
s and binders
in the production of paints and PVC
shows promise as a method of reducing smog pollution
.
One of over 1,000 species in genus Vernonia
, V. galamensis is native to East Africa
. It is grown in the region as an industrial oilseed. Its seed production is poor when it is grown outside of the equator
ial region, so cultivation in other places is not always economically worthwhile; however, further studies in the breeding of this species to generate more productive varieties may show promise. It requires loose, porous soil and long periods of dry conditions.
It is grown in many parts of Ethiopia, especially around the city of Harar
, with an average seed yield of 2 to 2.5 t/ha. It is reported that the Ethiopian strains of Vernonia have the highest oil content, up to 41.9% with up to 80% vernolic acid, and is used in paint formulations, coatings plasticizers, and as a reagent for many industrial chemicals.
Vernonia galamensis is a daisylike annual which is quite variable in appearance between individual plants. It produces a flower which may be blue or purple, with long petals surrounding a center made up of shorter petals called florets. The center is filled with seeds, some of which may have a hairy tuft called a pappus
. Depending on environmental conditions the plant may be squat and shrubby or extremely tall. It may send out few stems, each with one flower, or many stems with bunches of flowers.
When not found in cultivation, the plant may be found growing wild, often as a weed which invades disturbed areas and rangeland. A number of insects feed on the plant. Species of the moth genus Indent are sometimes known as vernonia worms due to their preference for Vernonia plants as food.
There are several subspecies:
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
, known for its use as an oilseed
Vegetable fats and oils
Vegetable fats and oils are lipid materials derived from plants. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure...
. This species, often called ironweed, is the largest source of vernonia oil
Vernonia oil
Vernolic acid is an organic compound and a fatty acid. This monounsaturated long chain carboxylic acid contains an epoxide. This isomer of coronaric acid was first definitively characterized in 1954...
, which is rich in a useful epoxy
Epoxy
Epoxy, also known as polyepoxide, is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener". Epoxy has a wide range of applications, including fiber-reinforced plastic materials and general purpose adhesives....
fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
called vernolic acid and is used to make plastics, rubbery coatings, and drying agents. Use of this oil as a replacement for traditional plasticizer
Plasticizer
Plasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...
s and binders
Binder (material)
-See also:*Adhesive or Glue*Cement*Paint...
in the production of paints and PVC
Polyvinyl chloride
Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...
shows promise as a method of reducing smog pollution
Smog
Smog is a type of air pollution; the word "smog" is a portmanteau of smoke and fog. Modern smog is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine...
.
One of over 1,000 species in genus Vernonia
Vernonia
Vernonia is a genus of about 1000 species of forbs and shrubs in the family Asteraceae. Some species are known as Ironweed. Some species are edible and of economic value. They are known for having intense purple flowers. The genus is named for English botanist William Vernon. There are numerous...
, V. galamensis is native to East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
. It is grown in the region as an industrial oilseed. Its seed production is poor when it is grown outside of the equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
ial region, so cultivation in other places is not always economically worthwhile; however, further studies in the breeding of this species to generate more productive varieties may show promise. It requires loose, porous soil and long periods of dry conditions.
It is grown in many parts of Ethiopia, especially around the city of Harar
Harar
Harar is an eastern city in Ethiopia, and the capital of the modern Harari ethno-political division of Ethiopia...
, with an average seed yield of 2 to 2.5 t/ha. It is reported that the Ethiopian strains of Vernonia have the highest oil content, up to 41.9% with up to 80% vernolic acid, and is used in paint formulations, coatings plasticizers, and as a reagent for many industrial chemicals.
Vernonia galamensis is a daisylike annual which is quite variable in appearance between individual plants. It produces a flower which may be blue or purple, with long petals surrounding a center made up of shorter petals called florets. The center is filled with seeds, some of which may have a hairy tuft called a pappus
Pappus (flower structure)
The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...
. Depending on environmental conditions the plant may be squat and shrubby or extremely tall. It may send out few stems, each with one flower, or many stems with bunches of flowers.
When not found in cultivation, the plant may be found growing wild, often as a weed which invades disturbed areas and rangeland. A number of insects feed on the plant. Species of the moth genus Indent are sometimes known as vernonia worms due to their preference for Vernonia plants as food.
There are several subspecies:
- V. g. galamensis
- V. g. nairobensis
- V. g. lushotoensis
- V. g. mutomoensis
- V. g. afromontana
- V. g. gibbosa