Classification and taxonomy of cannabis
Even though it is estimated that the cannabis plant has been accompanying humanity for millennia, confusion still exists today regarding the classification of its species or varieties. In fact, the debate on how to classify this plant has been active for more than two centuries: are the different varieties of cannabis typical of a single and very diverse species? Or is it a polytypic genre with several species? In this article we will investigate and explain the main differences between hemp and marijuana.
As we saw in our article on the origins of cannabis cultivation, the plant was first classified by Carl Linnaeus in 1753, and named Cannabis Sativa. However, Linnaeus only knew European hemp, and it was not until 1785 that Jean-Baptiste de Lamarck introduced a second species found in the mountains of India and with very different morphological features from the first, which he called Cannabis Indica. Much later, in the twentieth century, precisely in 1924, D.E. Janichevsky presented a third species found in Russia, Cannabis Ruderalis.
The debate continued until the 1970s, when William Emboden, Loran Anderson and Richard E. Schultes proposed the classification that is still the most popular among botanists and growers today, dividing the genus Cannabis into three distinct species: Sativa, Indica and Ruderalis. This classification is based on stable morphological differences observed in each of the three species, and is therefore the most used when talking about the different varieties of each species.
- Kingdom: Plantae
- Subkingdom: Tracheobionta
- Division: Magnoliophyta
- Class: Magnoliopsida
- Order: Urticales
- Family: Cannabaceae
- Genus: Cannabis
- Species: Cannabis Sativa L., Cannabis Indica Lam., Cannabis Ruderalis Janisch
The origin of hemp and marijuana
One of the main differences between hemp and what we colloquially call marijuana is the THC or tetrahydrocannabinol content of the latter. Indeed, while hemp varieties show a very low (or nonexistent) content in this psychoactive compound, the cannabis plants we often refer to as drug varieties do contain considerable amounts of this cannabinoid. But how did these varieties come to have such different traits? In 1976, Ernest Small and Arthur Cronquist proposed that it would have been mainly due to the human factor.
Over time, thanks to the selection and breeding carried out year after year, two very different types of cannabis would have been differentiated: one rich in THC and used for medicinal, religious and recreational purposes, and another with hardly any THC content, destined for the production of food and various materials and objects such as fabrics, ropes or baskets. As cannabis expanded from Asia, and thanks to the selection of growers in the areas where it took root, more and more different varieties appeared, each sharing characteristics with their distant relatives, but in turn developing their own unique traits.
So, the THC rich varieties would be what we now call “marijuana” (and in many cases “cannabis”), while those lacking this psychoactive compound and used industrially to obtain raw materials are generically called “hemp”. Within each of these types we can find hundreds of different varieties, from those offered as THC-rich, feminised seeds to hemp seeds that can be purchased by weight in any agricultural cooperative.
Differences between hemp and marijuana
Broadly speaking, we can point to differences in terms of morphology, chemotype and use to distinguish between hemp and marijuana. Marijuana (cannabis rich in THC) is usually more compact and branchy, has a much richer content of cannabinoids and terpenes and is usually cultivated and used for medicinal or recreational purposes. In contrast, hemp plants usually grow much taller (up to and over 5 meters), have very little lateral branching and usually a very low content in cannabinoids and terpenes (some of them do have considerable amounts of CBD, CBG or other compounds of particular interest in the therapeutic field). Today, hemp has dozens of applications in industry and for food, from the production of seeds to the manufacture of bricks for construction.
Given its characteristics, especially the height of the plants, it is almost impossible to grow hemp indoors, meaning that most of the hemp produced worldwide is outdoors or in greenhouses. On the other hand, and since the cultivation of marijuana is illegal in many places, indoor cultivation is the method chosen by many growers of this type of plant, and with good reason, cultivating indoors is much safer both for legal reasons and to avoid the attention of plant thieves or “rippers”.
Characteristics and uses of hemp
As we know, mankind has cultivated and used hemp for millennia, and has obtained different materials for an endless number of industrial or nutritional applications. Hemp is usually cultivated intensively, at a very high plant density, which is partly due to its low capacity to develop lateral branches. The height varies depending on the variety and growing conditions, although it is not uncommon for the plants to reach a height between 2 and 5 or 6 meters. The inter-nodal distance is very large, especially in those crops grown principally for fibre, for example, rather than seeds.
The stem is usually thicker, more woody, and also less hollow than that of many varieties rich in THC. They can present male or female flowers, although there is also a considerable number of monoecious specimens, in other words, hermaphrodites. Depending on the final use, which can range from the production of hemp seed oil, to fibre for cellulose, the producers will choose one variety or the other according on the characteristics of each one. These are some of the many uses of hemp:
- Paper production
- Materials for weaving (clothes, ropes, candles, etc.)
- Manufacture of biodegradable plastics
- Recyclable and biodegradable construction material
- Synthetic materials (aerospace and automotive industry)
- Seed production
- Seed oil
- Cosmetic industry (soaps, creams, etc.)
Beyond any shadow of a doubt, hemp represents an ecological and sustainable alternative that can greatly contribute to creating a better future for our planet, especially if practices such as the responsible use of pesticides and other toxic products are taken into account by growers.
We really hope that’s the case!
Bibliography consulted for this article:
- M. Lambert, D. Cannabinoids in Nature and Medicine (2009)
- Geoffrey William Guy; Brian Anthony Whittle; Philip Robson. The Medicinal Uses of Cannabis and Cannabinoids (2004)
- Small, E.; Cronquist, A. A Practical and Natural Taxonomy for Cannabis (1976)
- Schultes R. E.; Klein W. M.; Plowman T.; Lockwood T. E. Cannabis: an example of taxonomic neglect (1974)
- Michael Karus. European hemp industry 2001 till 2004: Cultivation, raw materials, products and trends (2005)