Trichomes: something so small yet so crucial to the world of cannabis. Trichomes, particularly the trichome heads, are where all the active phytochemicals are stored, which makes cannabis such a beneficial and therapeutic plant. Unlike visually assessing fruits on a tree, however, we can only fully see trichomes with the aid of a microscope.

This article will explore the world of cannabis trichomes and help our readers understand why trichomes are such an integral part of cannabis and how and why we assess trichome quality. Using a microscope to view trichomes, we can assess the quality and ripeness of the trichomes, similarly to how one might assess the quality of apples or grapes visually at the grocery store. 

What are Cannabis Trichomes?

“Trichomes are the hair-like-looking resin glands that primarily evolve on the bracts of a cannabis flower and produce all the phytochemicals.” 

Thomas Rothmeier, TDC Founder 

 

The trichomes (specifically, the capitate stalked trichomes) are where most phytochemicals are produced and stored. All the action occurs within the ‘head’ of the trichome, with the secretory disks producing phytochemicals, which are secreted and stored in the secretory cavity located in the top half of the trichome head.  

Excerpt from TDC Cannabis Microscopy Course (Diagram credit: Samuels Lab, UBC)

Phytochemicals such as cannabinoids (THC, CBD, CBG etc.) contribute to the therapeutic benefits of cannabis. However, cannabinoids do not act alone. The trichomes also hold terpenes (limonene, pinene, linalool, etc.), which hold therapeutic value and are responsible for many of the aromas found in cannabis. Thiols and Thioltates make up the more diesel, skunky, and cheesy aromas, whereas esters produce more fruity aromas, such as bananas and apples.

"It's all in the heads" - TDC Grading Workshop at Stick & Stone

Furthermore, flavonoids contribute to the colour and therapeutic value of cannabis. These phytochemicals work in tandem in an entourage effect on each of our Endocannabinoid Systems (ECS). Depending on the cultivar, this may result in the consumer being “high.”

What is the purpose of Cannabis Trichomes? 

With such a versatile plant, surely trichomes do not just get humans high, and that is it? Trichomes are like the plant in that they are just as versatile. Trichomes are an advanced defence system that cannabis has developed over many years to protect itself from environmental dangers. There are two different types of trichomes: Non-glandular and glandular. 

Trichomes: An Advanced Defence System

Cannabis is an incredibly versatile plant, and trichomes, the tiny structures found on its surface, serve a purpose far beyond simply getting humans high. Trichomes are as multifaceted as the plant itself. They function as an advanced defence mechanism that cannabis has evolved to safeguard itself.

These trichomes come in two distinct types: non-glandular and glandular:

Non-glandular:

• Cystolythic 
• Unicellular 

Glandular 

• Simple Bulbous 
• Complex Bulbous 
• Capitate Sessile 
• Capitate Stalked

Non-glandular trichomes protect the plant from insects, predators, and fungi. There are two non-glandular trichomes: The cystolythic, which resembles a bear claw and protects against predators and fungi, and the unicellular, which resembles a spiky hair and protects the plant against UV light and aids in water absorption. 

UBC Samuel Lab research shows that capitate sessile trichomes are the precursor for capitate stakled trichomes. Bulbous trichomes have two distinct categories: simple bulbous and complex bulbous. A simple bulbous and its sibling complex bulbous trichomes have a bulbous head and will be the smallest at around 10-30 micrometres. These trichomes will be the first ones to turn amber in colour.  

Excerpt from TDC Cannabis Microscopy Course

Terpenes acting as bug repellent: A ratio of sesquiterpenes and monoterpenes can affect the viscosity of the resin glands. The plant can signal the resin glands to increase the density by altering the balance if the plant feels like it is under attack from insects. This increased amount of terpenes in the resin glands can make insects stick to the plant as the terpenes and cannabinoids act. 

The capitate sessile and capitate stalked have the word Capitate (‘with head’) in their name due to their head-like appearance. The capitate sessile is the precursor of the capitate stalked trichome. The word sessile stands for “sitting” and holds a lower amount of phytochemicals compared with that of the capitate stalked. The capitate sessile trichomes also contain a higher proportion of sesquiterpenes, whereas the more mature capitate stalked trichome holds a higher proportion of the more volatile monoterpenes.

The capitate sessile is about 25-100 micrometres in size. Finally, there is the capitate stalked.  This resin gland is the one that holds the most phytochemicals out of all the other trichomes. Capitate stalked trichomes are typically 50-500 micrometres in size. 

What Else Do We Know About Trichomes?

So, what else do we know about trichomes? The UBC Samuel Labs study showed the difference between a capitate sessile and a capitate stalked underneath a microscope, showing for the first time how the capitate sessile eventually grows into a capitate stalked. 

Excerpt from TDC Cannabis Microscopy Course (Diagram credit: Samuels Lab, UBC)

An SFU study used machine learning to automate and estimate trichome density, head size, and colour in situ. This means we can better understand each cultivar's different variations for a harvest date. Ex: There is a fifteen-day gap between the earliest (Pink Kush 55 days) and the latest (White Rhino 70 days). 

Conclusion 

So, what do we know about trichomes? We know trichomes are hair-like resin glands that hold phytochemicals in their secretory cavity. These phytochemicals contain the majority of compounds that provide cannabis' therapeutic benefits and work together in an entourage effect to produce a complex and diverse range of possible experiences. Trichomes can only be seen properly through a microscope. We also now know that trichomes help protect the plant from predators, insects, UV light, and fungi. To learn more about trichomes, sign up for the The Different Collective Cannabis Microscopy course. Be sure to share with your friends and others!  

Author Bio

 

Coming to you straight out of British Columbia, Simone has been consuming cannabis since high school and joined the legal market as a budtender in late 2021.  She is showcasing the craft, the dank, and the shake of the West Coast market. Simone has gone through CannaReps Level 1, The Different Collective Cannabis Microscopy Course, The Trichome Insitute’s Cooking with Cannabis, and Extracts and Concentrate course.  Simone also posts reviews on YouTube and CannaViews. Let’s blast some Mother Mother and get ready to laugh like Seth Rogen.

 

References

Livingston, S. J., Quilichini, T. D., Booth, J. K., J. Wong, D. C., Rensing, K. H., Laflamme-Yonkman, J., Castellarin, S. D., Bohlmann, J., Page, J. E., & Samuels, A. L. (2020). Cannabis glandular trichomes alter morphology and metabolite content during flower maturation. The Plant Journal, 101(1), 37-56. https://doi.org/10.1111/tpj.

Punja, Z.K., Sutton, D.B. & Kim, T. Glandular trichome development, morphology, and maturation are influenced by plant age and genotype in high THC-containing cannabis (Cannabis set al. inflorescences. J Cannabis Res 5, 12 (2023). https://doi.org/10.1186/s42238-023-00178-9