Definition - What does Bulbous Trichome mean?
Bulbous trichomes are the smaller of the two main types of glandular trichomes (the larger being the much more visible capitate stalked trichomes).
Bulbous trichomes measure 15 to 30 micrometers each. They form on the entire plant, but even though they grow close to the surface of the plant, bulbous trichomes are so small you won't be able to see them without a microscope.
Hydrolife explains Bulbous Trichome
You can find bulbous trichomes on any part of the cannabis plant above the ground. They begin forming when the plant is young and are present on every part of the plant to help protect it from the elements.
Some studies suggest that the bulbous trichomes alert the plants to insect movements. For example, in one study, when a bug burst a bulbous trichome, it caused for chemical secretions that developed more glandular trichomes, and thus protected the plant.
Another purpose of bulbous trichomes is a form of sunscreen for the cannabis plant as it protects them from UV rays. Bulbous trichomes also help protect against high winds and low humidity by keeping water close to the surface. When the trichomes mature and fill with resin, a protrusion emerges and you can feel the slight bumps on the stalk.
Bulbous trichomes are made up of two parts. The foot or stalk is made out of 1 to 4 cells, while the head is a mushroom-looking top that is also 1 to 4 cells. The head secretes compounds and it is clear.