The Thunder (Ligustrum lucidum) is an evergreen tree belonging to the Oleaceae family. It is native to China, Korea and Japan, and is widely cultivated in various parts of the world as an ornamental tree, although the naturalization of this plant in countries such as the United States and Canada has brought serious problems as it is a very destructive colonizer.
The common name thunder refers to the glistening leaves of this tree, and the same refers to the specific epithet, which comes from the Latin lacidus-a-um, which means luminous.
Ligustrum lucidum. Taken by Fanghong
Thunder is a small tree growing plant, sometimes growing as a shrub. It can measure an average of 3.5 meters in height and is highly branched, thus presenting a globose crown.
Meanwhile, the leaves are arranged oppositely on lenticelled twigs. Each leaf has an ovate or elliptical shape with an acuminate apex, and with variable coloration between the abaxial and adaxial surfaces. The flowers are hermaphroditic, very showy white, and are organized in terminal inflorescences with a pyramidal shape.
Ligustrum lucidum is a native species of the Asian continent, however it is common to find it in gardens and streets of various cities around the world. In its unnatural range this plant is dangerously invasive and represents a risk to the local flora.
On the other hand, the fruit of this plant is slightly toxic for consumption, however it has antibiotic properties. In traditional Chinese medicine, this tree has been used for over 1000 years as a tonic and diuretic.
characteristics
Tree
Ligustrum lucidum is a shrub or perennial tree of small size that measures between 2 to 5 meters in height. It has branching from the base and a globose crown. In turn, the bark of the trunk is smooth with a color that varies from brown to greyish.
Leaves
Thunderbolt leaves vary in shape from ovate or elliptical to oblong-lanceolate and are 6 to 13 cm long by 2.5 to 5.5 cm wide. The base of the leaf blade is rounded, while the apex is acuminate. On the other hand, the leaves are arranged in the opposite way.
The Thunder. Taken by Fanghong
The margin on its side is entire and the adaxial surface is dark green, while the underside is pale green. Furthermore, the leaves are devoid of pubescence and have a leathery consistency.
In turn, the median nerve is more prominent on the underside with 4 to 11 pairs of secondary nerves. Each leaf hangs from a petiole 1 to 3 cm long, ribbed and green or brownish-purple in color.
flowers
The flowers are grouped in terminal panicles with a pyramidal shape and with a length of 7 to 16 cm. The flowers are small with a greenish-white color, and can be sessile or sub-sessile, with a pedicel 0 to 0.5 mm long.
The calyx is devoid of pubescence and the corolla tube is equal to or slightly shorter than the lobes. While the two stamens have filaments 1 to 3 mm long with oblong, yellow anthers, 1 to 1.5 mm long.
Inflorescence of Ligustrum lucidum. Taken by Fanghong
Fruit
The fruits of thunder are globose drupes with ovoid or flat shape 5 to 9 mm long. They are purplish-black or bluish-black when ripe. Each fruit contains 1 to 2 seeds with a hard endocarp.
Fruits of thunder. KENPEI
Habitat and distribution
Ligustrum lucidum is a tree native to China, Korea and Japan, and has a worldwide distribution because it is used as an ornamental tree to decorate streets and gardens. In the states of Texas, Louisiana, and Arkansas, thunder is a highly invasive plant where clumps of multiple stems are seen.
In Argentina this tree has been called an invasive species since it has been shown that it consumes a greater amount of water, especially in the dry season due to its longer phenological activity compared to the local forest; which implies that it modifies the hydric functioning of these ecosystems.
The results of other studies show that this plant produces numerous fruits throughout the year and that its seeds have a high germination rate in a wide range of environmental conditions, which makes it very competitive with local species.
Also, thunder is a relatively shade tolerant plant and it is unclear whether it is part of the primary or secondary succession.
Ligustrum lucidum grows in warm and humid environments, with an annual rainfall range of 700 to 1600 mm. It is found in a wide range of habitats such as open forests, grasslands, polluted areas, and around rain forests.
From the ecological point of view, the Pyracantha angustifolia species behaves as a nurse plant with L. lucidum, thus increasing the survival of this plant in the juvenile stage. Other plants like Condalia montana and some thorny bushes help in the establishment of thunder.
Taxonomy
The genus Ligustrum is one of the 25 genera that are part of the Oleaceae family. This family has varied its taxonomic position, although it is currently in the order Lamiales.
- Kingdom: Plantae.
- Subkingdom: Viridiplantae.
- Infra kingdom: Streptophyte.
- Super division: Embriofita.
- Division: Tracheophyte.
- Subdivision: Eufilofitina.
- Infra division: Lignofita.
- Class: Spermatophyte.
- Subclass: Magnoliofita.
- Superorder: Asteranae.
- Order: Lamiales.
- Family: Oleaceae
- Genus: Ligustrum
- Species: Ligustrum lucidum
Medicinal properties
Ligustrum lucidum has been used for over 1000 years in traditional Chinese medicine. The fruits of this tree have antibacterial, anti-cancer properties, and are used as a cardiotonic, as a diuretic and as a tonic.
This plant has been used to treat ailments related to a weak liver and kidney, and for menopausal problems. Furthermore, thunder has been shown to have properties to treat blurred vision, cataracts, rheumatic and back pain, and insomnia.
Recent studies have shown that the use of extracts of this plant increases the levels of white blood cells in the blood, thus being a potential candidate in the treatment against HIV.
References
- Aragón, R., Groom, M. 2003. Invasion by Ligustrum lucidum (Oleaceae) in NW Argentina: early stage characteristics in different habitat types. Journal of Tropical Biology, 51 (1): 59-70.
- CAB International. (2009). Ligustrum lucidum (broad-leaf privet). Taken from: cabi.org.
- De Juana, JI 2009. Updated taxonomy of the genus Ligustrum L. Bouteloua, 6: 16-71.
- ITIS Report. (2019). Ligustrum L. Taken from: itis.gov
- Nesom, GL 2009. Taxonomic overview of Ligustrum (Oleaceae) naturalized in North America North of Mexico. Phytologia, 91 (3): 467-482.
- Practical Plants. (2013). Ligustrum lucidum Chinese privet. Taken from: practicalplants.org.
- Sánchez, JM (SF). Ligustrum lucidum WT Aiton. File prepared for the Murcia City Council, Department of the Environment.
- Zamora-Nasca, L., Montti, L., Grau, R., Paolini, L. 2014. Effects of the invasion of the privet, Ligustrum lucidum, on the hydric dynamics of the Yungas of northwestern Argentina. Bosque, 35 (2): 195-205.