Article by Nanette Porter, Medical Jane
What are trichomes?
If you look closely at a healthy cannabis plant, then you will undoubtedly notice the many glistening translucent resin glands protruding from the buds. These resinous outgrowths are known as trichomes.
Trichomes house the key components of the plant that give it its therapeutic and psychotropic properties. These glandular structures are predominantly responsible for the biosynthesis of cannabinoids, the biologically active compounds unique to the Cannabis plant.
Barely visible to the naked eye, trichomes are better observed through magnification (at least 40x). But at close examination, you can see the trichomes protruding from the flowers and the small leaves that are interspersed among the flower clusters. The most abundant concentration of trichomes can be found on bracts of pistillate (female) plants. The pistillate flowers contain a greater density of glands than the leaves.
Trichomes should not be confused with the pistils on the flowers of a female plant. The pistils house the plant’s reproductive organs and are often covered with gooey resin. The pistils are fairly easy to distinguish as they are covered with lots of pistillate hairs. These wispy “plant hairs” typically begin white in color and slowly change in color to hues of oranges and reds as they age, and then to brown as they near death.
Types of trichomes
Plant trichomes come in a variety of shapes, sizes and cellular composition. Trichomes of the Cannabis plant have been divided into two types, namely glandular and non-glandular. These types of trichomes are distinguishable on the basis of their capacity to produce and secrete, or to store significant quantities of secondary metabolites.
Non-glandular trichomes are hair-like extensions resembling leaf hairs, with a slender pointed apex. They protect the plant from its environment, mainly through physical means (e.g., restricting access to animals and insects, preventing water losses or light degradation, and fungal infection). It is characteristic of cannabis to find non-glandular trichomes on both the top and bottom of leaves.
Non-glandular trichomes fall into one of two categories:
- Cystolithic trichomes have a characteristic bear claw shape and may have calcium cystoliths resembling knobs visible at their bases. They are found on the upper surface of the leaves and range from 150 to 220 microns in height. Frequently, the trichome is broken and the knob freed.
- Non-cystolithic trichomes are found most often on the lower side of the leaves, bracts, and bracteoles and tend to be fine and slender in shape.