BlogRespecting science: Correcting cannabis nomenclature

Respecting science: Correcting cannabis nomenclature

9 min read

Editorial Team

Respecting science: Correcting cannabis nomenclature
The cannabis industry was left unregulated for the best part of 50 years. A result of this has been the dissemination of incorrect cannabis terminology that, unfortunately, still plagues the industry today. Now that products are legally regulated for medicinal purposes and industry experts and professionals can share their knowledge without fear of arrest and imprisonment, the proper language for cannabis constituents is starting to reach the mainstream public.


Words with distinct meanings have been used interchangeably with others creating confusion, but their characteristics are important for specific scientific nuance. Correct cannabis terminology is important. If everyone uses different words to describe the same thing, how will we ever know we are talking about the same thing?

Indica, Sativa, Hybrid

Just as the wider public is learning what cannabis is and how patients decide which strains to use, the scientific community in the medical cannabis industry have made it known that the way strains have traditionally been categorised doesn't make scientific sense. The word strain should really be cultivar or variety. 

Until now, consumers and seed producers have sub categorised cannabis into three main groups. Indica, sativa and hybrid. The confusing part is that the groups are used for two different purposes. 

The first is to distinguish the morphology in the look and growing style of the plant. Indica plants are traditionally known for their broad finger leaves that are almost oval, similar in shape to a rugby ball. The plants grow short and stocky like shrubs. They have lateral branches; the buds are typically round and fairly dense. 

Indica was a term attributed to all produce from India and was "from Indian origin". This kind of cannabis was first discovered in India and recorded by botanist Jean-Baptiste Lamarck in 1975. Plants with this structure typically grow in the northern hemisphere. 

Sativa plants are traditionally known for their tall and slender structure. They grow vertically with less side branching, greater internode length and produce arrowhead flowers. Plants with this structure grow naturally in equatorial locations. 

This difference in leaf type is seen across the globe, and the reasons for it are believed to be evolutionary adaptations caused due to the different light and growing conditions.

Cannabis landrace varieties growing in the Indian Hindu Kush mountain region display the broad oval leaves described above. Still, the narrow leaf varieties exist at the bottom of India in Kerala. 

A hybrid is a cross between an Indica and a Sativa. Today, 99% of cannabis genetics are so-called hybrids. 

The second use of the three terms is to differentiate the effect different varieties of cannabis produce in people who take it. Indicas are said to be sedative or relaxing varieties and have more of an effect on the body. Sativas are energising, mentally stimulating and are considered to be more cerebral. 

As useful as this has been for many people trying to navigate the medical cannabis varieties available, it's all based on perception, without any scientific grounding, giving a lot of room for error. 

The variety growing in Kerala may look different but have similar effects to the variety growing in the Hindu Kush mountains, which doesn't match up with the unscientific and generalised categories based on a plant's look. There needs to be a better way to categorise varieties that considers the scientific differences.

What are we calling them instead? 

Robert C. Clark is a respected cannabis botanist and author on the subject. He has been studying cannabis in the wild and in labs for over 50 years. In 2013 the botanist proposed a new categorisation system for cannabis regarding morphology. Robert C. Clark suggests the terms Broad Leaflet Drug (BLD), Broad Leaflet Hemp (BLH), Narrow Leaflet Drug (NLD) and Narrow Leaflet Hemp (NLH) are better suited to distinguishing a plant type which will denote its medical usefulness. 

When selecting the right medical variety for a health condition and set of symptoms, the terpene profile will distinguish which beneficial effects it will likely have. Terpenes' effects differ when combined with other terpenes in different ratios, so it is still a complex way of navigating which cannabis variety will work best for you if you are inexperienced. 

Unfortunately, medical cannabis is only regulated for THC and CBD. There is no legal requirement that cannabis-based medicinal products have terpenes present or in what amounts to be suitable for different conditions. 

Anatomy of a cannabis flower

Trichomes not Trichromes

A common but simple mistake that I overhear all too often in the legal medical cannabis industry is someone referring to trichomes as trichomes, adding an extra "r" in the word's second syllable. Trichome is a beautiful word for an intriguing part of the plant. It's the part where the medicine is made, and medicinal cannabis wouldn't be the same without them. 

Trichomes are ubiquitous in the plant world, making up different types of epidermal hairs growing out of the surface of a plant. The word trichome comes from the Greek word trachoma, meaning "growth of hair", which might make sense when you learn that the harvest from the cotton plant is a collection of trichomes! Far from hairs on cannabis, the trichomes found on this medicinal crop are sticky to the touch, and the exterior shell is easily broken when growing on the plant. Trichomes make up the "kief" or "crystals" in the bottom of a medicinal cannabis grinder, and when this is pressed together, it is known as hash or hashish, which are not medically regulated products. 

Under the microscope, cannabis trichomes appear clear to cloudy mushroom-shaped appendages with a globe on top. As plants progress through the flowering stage, the trichome globes start turning amber. The cannabis plant has three types of trichomes; bulbous, capitate sessile and capitate stalked trichomes. Trichomes are little factories that produce cannabinoids, terpenes, esters, thiols and other pharmaceutically active compounds. 

Trichrome sounds like a futuristic paint job on something Mr Spock of Star Trek might start discussing. 

Flowers: Colas, buds and nugs.

No, not the drink, although I'm sure it would be popular. A cola is the flowering top of a branch growing vertically that has no other protruding branches. Colas are stacked inflorescences growing along the stem in a raceme formation. Outdoors can reach a metre in length, but indoors, they are typically less than a foot. Cola is the Spanish word for tail. Each inflorescence also has a cola at the top of it, the terminal flower. A term less used today for flowers that would grow one individual flower on top of another at the tip of a cola was called fox tailing.

In wider botanical terms, a bud is the name given to any new growth in its first stages; it could be a new branch, a leaf or a flower. A bud is not a trimmed ready-to-use cannabis "nugget", as it is known in the cannabis culture.  

The oldest flowers grow at the bottom of a "nug" or inflorescence, and the newest and last to grow are at the top. 

Bracts, sepals and calyx

Cannabis inflorescences have many round-to-teardrop-shaped micro leaflets that stack up in a pyramid-style tessellation, alternating with leaf sets. What appears to be a single flower is a cluster of flowers. Each one of these teardrop leaflets pods is an individual cannabis flower that will produce one seed when fertilised - something cultivators want to avoid happening in a medicinal facility. This plant part is often mistakenly called a calyx; the correct term is a bract. Trichomes cover the bract's exterior surface.   

A single cannabis flower consists of a bract constructed of two tightly growing leaflets called sepals, covering an ovule where a single seed forms. Out of the sepals grow pistils. 

Cannabis flowers do have calyx. However, it is almost impossible to see unless you dissect an individual cannabis flower with some tweezers. The calyx is a six-cell thin protective layer that encases and protects the ovule where a seed will form.

The "little orange hairs" are called "stigma."

Out of each bract grow two white hair-like structures. These are mistakenly called pistil, but the term pistil comes from the flower as it starts to show signs of fertility. These are the stigma. Papillae appear on the surface of the stigma, making it look slightly fuzzy to the naked eye. Papillae are even smaller hairs used to catch and grip onto the pollen's surface as the wind blows it past the cannabis flowers. Once the papillae have caught a pollen grain, a signal is sent beginning the fertilisation process, and seed production in that individual bract begins. 

Once a pistil is pollinated, it will turn orange-brown and die for no further purpose. The plant has no further use for it. The pistils may turn orange-brown before pollination due to damage caused by touch or because the pH of the root's growing conditions is too alkaline, which stresses the plant into trying to finish too early. This stress could lead to the plant turning hermaphrodite and producing male flowers and pollen, forcing the crop to produce seed. A disaster for a medicinal cannabis cultivation facility. 

Anatomy of the cannabis plant

Nodes and Internodes

These two closely related plant parts, nodes and internodes often get mixed up or used interchangeably, but there is a difference. A plant node is an individual branch growing off of a main stem. The internode is the gap that appears between them. Equatorial varieties tend to have a greater internode length, and northern hemisphere varieties tend to be shorter. This length factor is believed to be partly controlled by the levels of plant hormone gibberellin, which can play a role in determining the spacing of nodes and the height of plants. 


Well, I hope you have found this quick run down helpful, and if you've learned something new, you will try to integrate it into your cannabis lexicon. These are just a few of the main victims of misused cannabis vocabulary; there are more, and if you've found this as fascinating as I do, please feel encouraged to read more on the subject from authors like Mel Frank and Robert Connel Clark, who have spent their entire careers making cannabis botanical information accessible to the public. They are some of the most informed experts in the field. As the industry develops and progresses into mainstream medicine, conversations around cannabis will become more normal and acceptable. Using the correct terminology will help create a better understanding from the offset and bring greater respect for industry professionals in the wide scientific, horticultural and medical communities.

It is important to seek medical advice before starting any new treatments. The patient advisors at Releaf are available to provide expert advice and support. Alternatively, click here to book a consultation with one of our specialist doctors.

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Editorial Team

Article written by the Releaf Editorial Team, a group of seasoned experts in cannabis healthcare, dedicated to enhancing awareness and accessibility in the field through their wealth of knowledge and experience.

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