You probably know that trichomes are the sticky, resinous glands that cover mature leaves and flowers of many types of plants, but you may not know that there are actually three trichomes with varying physical structures that we find on cannabis.
Though they are different shapes and sizes, all three trichomes found on cannabis flowers produce the same cannabinoids, terpenes, and other chemical compounds that make marijuana unique. However, we must remember that each variety of cannabis produces a different mixture of those compounds depending on the genetics of the strain. Here we touch on the three basic types of trichomes that coat the surface of cannabis flowers: bulbous, capitate-sessile, and capitate-stalked.
1. Bulbous Trichomes
The smallest type of trichome found on cannabis is the bulbous trichome, which measures just 10-30 micrometers in length and is barely visible to the naked eye. Bulbous trichomes form sparsely across the surface of the plant, but each one is only made up of a few cells that comprise a short “stalk” and a gland head that secretes resin. As this gland swells it sometimes forms a small, “bulbous” protrusion on the top of the membrane.
2. Capitate-Sessile Trichomes
Capitate-sessile trichomes are medium-sized glands that cover cannabis plants more densely than bulbous trichomes. This type of trichome consists of a single-cell stalk with a larger, rounded gland on top. This gland usually consists of 8-16 cells that group to form a convex rosette that lies flush on top of the stalk. These globular-shaped glands usually measure between 25 to 100 micrometers in length.
3. Capitate-Stalked Trichomes
The largest and most abundantly found trichome type we find on cannabis plants is the capitate-stalked trichome. Capitate-stalked trichomes appear during the flowering phase and coat the area in and around the calyxes (protective outer layer of small leaves) that surround new buds. This type of trichome is what most cannabis growers are looking for when harvesting a crop, as they produce the highest concentrations of the plant's unique chemical compounds. You can easily see the elongated stalk and swollen gland head with the naked eye or with a hand-held magnifying glass, as capitate-stalked trichomes can reach lengths of 50-500 micrometers.