Every species on the planet has a two-part name that is known as the scientific name, Latin name, or binomial name. Carl Linnaeus is credited with coming up with this naming system.
Scientific names are always written in italics. The first part of the name is the genus, and always begins with a capitalized letter. The second part of the name is the species, and is always written in lower case. For instance, the scientific name for apple is Malus domestica, where Malus is the genus and domestica is the species. Humans are Homo sapiens. When dealing with herbs and essential oils, it is important to use the scientific name to identify the species, and there are crucial reasons for this.
1. The Same Common Name Can Be Used for 2 Different Plants
The common name of tea tree can be used for different plant species, two of which are Melaleuca alternifolia or tea tree Australia and Leptospermum scoparium or tea tree New Zealand. It is believed that their shared history is to blame. English Captain James Cook and his crew consumed tea from both trees during their explorations of Australia and New Zealand in the 1700s, thus resulting in their common name of tea tree (Petersen, 2010). In addition to their shared name they have other similarities, but also distinct differences.
Melaleuca alternifolia and Leptospermum scoparium essential oils are obtained from trees belonging to the Myrtacea family (Petersen, 2014b). But, M. alternifolia comes from the leaf of the Melaleuca alternifolia tree, which is a grown in swamp-like ground along the coast of Australia, and L. scoparium essential oil is obtained from the manuka tree, which although native to New Zealand, is also found in Australia, New Guinea, and Southeast Asia. Manuka was originally considered a weed, but grew in popularity over the years and now the herb is obtained through sustainable harvesting (Petersen, 2014b).
Essential oil of both have sharp scents, but that of M. alternifolia has a spicy scent and is white or pale yellow, and that of L. scoparium has a sweet scent and is usually clear yellow to brown (Petersen, 2014b).
Both are analgesic, antibacterial, antifungal, anti-inflammatory, antimicrobial, antiparasitic, antipruritic, antiseptic, antiviral, antizymotic, deodorant, diaphoretic, expectorant, fungicidal, germicidal, immune stimulant, insecticide, and vulnerary (Petersen, 2014b). They also reduce muscle tension and decrease contractions in the uterus (Lis-Balchin, 2006). But, the action as antiseptic, antifungal, and antibacterial is stronger in L. scoparium than in M. alternifolia (Petersen, 2010). L. scoparium can also be used as an antispasmodic, antiasthmatic, antianxiety, pain reliever, anesthetic, aphrodisiac, sedative, and vulnerary (Petersen, 2014b). Neither of the two oils is recommended for use while pregnant or nursing (Lis-Balchin, 2006).
M. alternifolia and L. scoparium act against bacteria, viruses, fungi, and other microorganisms, such as Listeria monocytogenes, Escheria coli, Pseudomona aeruginosa, Candida albicans, several Streptococcus species, several Staphylococcus species, and others (Petersen, 2014b). However, L. scoparium has activity against MRSA, and a study showed that M. alternifolia did not show statistically significant effect against MRSA (Blackwood et al., 2013). In addition, M. alternifolia is an antiviral against Herpes simplex type 2 (Petersen, 2014b).
M. alternifolia can be used externally to help heal burns, scalds, insect stings and bites, acne, and boils (Petersen, 2014b). L. scoparium can be used externally for the same reasons, as well as eczema, dermatitis, psoriasis, sores, splinters, sunburn, ulcers, warts, and wounds. Both essential oils are useful disinfectants for cleaning and laundry, as mouthwash, and water purifiers (Petersen, 2014b).
2. Plant Species Can Have Different Chemotypes
Chemotypes are different chemical expressions of the plant’s genes that result in different chemical compositions within species of the same plant and thus different actions in the body (Petersen, 2014a). For instance, there are four chemotypes of rosemary or Rosmarinus officinalis, each producing different constituents. R. officinalis ct 1,8 cineole has expectorant action; R. officinalis ct camphor, borneal is a stimulant and analgesic pain reliever; R. officinalis ct verbenone, bornyl acetate can act as an abortifacent; and R. officinalis ct myrcene has analgesic effects (Petersen, 2014a).
3. Plant Species Can Have Hybrids
Lavender is perhaps the most commonly used essential oil in aromatherapy (Buckle, 2003), but it comes from various plant sources.
Lavandula officinalis is also known as true lavender, and to complicate things further, it has a second scientific name of Lavandula angustifolia. It comes from a dwarf shrub that is distinctly free of camphor, and is grown in small areas in France above 2,000 feet, such as in Southern France and the French Alps (Petersen, 2014a). The plant yields small amounts of essential oil, but it is considered to be the finest form of lavender essential oil (Petersen, 2014b).
Lavandula latifolia is commonly known as spike lavender and Lavandula spica (Rhind, 2012). Its shrub is grown in the Northern Mediterranean region, Japan, Tasmania, and the US (Petersen, 2014a). It is a harsh herb that unlike L. officinalis, smells strongly of camphor, and is used to scent soaps (Petersen, 2014b), as well as a stimulant, muscle ache and pain reducer, and expectorant (Rhind, 2012).
Lavandula latifolia x l. angustifolia is a hybrid between true lavender and spike lavender that is found in France (Petersen, 2014a). It is commonly known as lavandin, and also has the scientific name of Lavandula x intermedia (Rhind, 2012). It is a sterile plant, but in some cases has stronger action than its parents. Its essential oil is high in camphor, unlike that of L. officinalis, and has been used as a mucolytic, expectorant, and analgesic (Rhind, 2012). Commercially, lavandin is used in aromatherapy, as a fragrance, and as an insecticide and herbicide (Petersen, 2014b). The plant is found readily, yields high amounts of essential oil, and because its cultivation and harvest can be done by machine, it offers a more economical choice for essential oil than its parents (Petersen, 2014a).
Lavandin is not as effective in its soothing, balancing, and antimicrobial properties as L. officinalis. L. latifolia has 1,8-cineole, which is not found in lavandin, and acts as an expectorant and anti-inflammatory (Petersen, 2014a). L. officinalis has been used as a relaxant, spasmolytic, tonic (Buckle, 2003), stress-reducer (Rhind, 2012), sedative, and to reduce anxiety (Petersen, 2014b). Lavandin is also a sedative and reduces anxiety, but is less strong than L. officinalis (Petersen, 2014b). In contrast, L. latifolia increases alertness (Petersen, 2014a).
All types of lavender have household uses as fragrant soaps, air fresheners, deodorizers, insect repellents, and air disinfectants. They can also be used in perfumery, however some believe that those species with higher ester content, such as L. officinalis, are the most potent (Petersen, 2014a).
It is important to use the scientific names when identifying herbs and essential oils, given that the same common name can be used to identify 2 different plant species, as is the case with tea tree. Scientific names also identify chemotypes of the same plant species, each of which can have different action in the body, as occurs with rosemary. Scientific names identify hybrids of two different species, which have different properties and actions than its parents, as is the case with lavender.
Blackwood, B., Thompson, G., McMullan, R., Stevenson, M., Riley, T. V., Alderdice, F. A., Trinder, T. J., Lavery, G. G., & McAuley, D. F. (2013). Tea tree oil (5%) body wash versus standard care (Johnson’s Baby Softwash) to prevent colonization with methicillin-resistant Staphylococcus aureus in critically ill adults: a randomized controlled trial. Journal of Antimicrobial Chemotherapy, 68, 1193-1199. doi:10.1093/jac/dks501
Buckle, J. (2003). Clinical Aromatherapy: Essential Oils In Practice (2nd ed.). London, United Kingdom: Churchill Livingstone.
Lis-Balchin, M. (2006). Aromatherapy Science: A Guide for Healthcare Professionals. London, United Kingdom: Pharmaceutical Press.
Petersen, D. (2010). Not All Manuka Essential Oil is Created Equal. Portland, OR: American College of Healthcare Sciences.
Petersen, D. (2014a). Aroma 501 Aromatherapy Science. Portland, OR: American College of Healthcare Sciences.
Petersen, D. (2014b). Aromatherapy Materia Medica: Essential Oil Monographs. Portland, OR: American College of Healthcare Sciences.
Rhind, J.P. (2012). Essential Oils: A Handbook for Aromatherapy Practice (2nd ed.). London, United Kingdom: Singing Dragon.