Most of us are middle class schleps who majored in one thing or another in college and show a propensity for a particular skill niche, such as engineering, management, writing, or design. When we began seriously using cannabis, we might have perceived it to be a performance enhancer. But we probably didn’t think that adopting the cannabis lifestyle would make us better botanists.
During the late summer of 2015, a friend and I attended a college town farmer’s market where she found an interesting and didactic houseplant. It gave off no aroma. However, when the leaves were rubbed, a strong scent of lime was transferred onto one’s fingers. In this particular plant, the odor was stronger than an actual lime, but so “lime like” that it defied description. Until you rub and smell one of these babies, you’re clueless. This plant brings new meaning to the term “essence.”
After some investigation, it was learned that this succulent, fleshy herb is a plectranthus amboinicus variety, meaning it is easy to grow, from a southern climate (in this particular case, Honduras), and used mostly as a decorative plant.
Also known as “Cuban Oregano” and “cerveza ‘n’ lime,” this herb can be used for a variety of purposes, from making a mild tea to treat digestive problems, respiratory ailments, and even arthritis to being used as a topical and rubbed on the skin as a cream to naturally repel insects.
Wrote Karen Lynn at Lil’ Suburban Homestead:
“This herb is my very favorite right now because it propagates so easily and it has kind of a distinct intense lemony/lime taste…a great compliment to Mexican cooking and it has a property in it that helps to neutralize spice or capsicum.”
Trichomes: Not Just for Cannabis
Because of what cannabis has taught me about the plant anatomy of resin-bearing herbs and flowers, I know that the “hairs” on the leaves are probably trichomes (resin glands) or something very similar. I’m fairly certain they’re trichomes, because there are actually more than a dozen types of these glands that commonly appear in thousands of plants, so they’re somewhat versatile and vary in appearance and specific function.
I’m also fairly certain that the strong lime scent on my friend’s plant (pictured above from her back deck) is produced by these densely populated, nearly microscopic trichomes on the leaves that produce a variety of terpenes. Terpenes are simply chemicals, or molecules, that serve many purposes within the plant, chiefly the production and conveyance of odors.
In cannabis, trichomes are responsible for the manufacture of both cannabinoids and terpenes. Cannabinoids include that infamous euphoric seductress, THC, and another that eliminates seizures in epilepsy patients and carries great medicinal promise, CBD.
Terpenes, while famous for producing specialized aromas and available in nature in more than 20,000 varieties of plants, appear in cannabis in about 200 types. In fact, 10-30 percent of the resin produced by smoked cannabis is the result of terpenes. One of these terpenes, limonene, is—among other things—responsible for the lime or citrus aroma of some strains of marijuana, as well as many other plants.
Limonene: Root Cause Found
Limonene is a terpene that conveys an odor of citrus, juniper, rosemary, or peppermint. It is a major part of what gives limes their citrus punch, as well as oranges, tangerines, lemons, and grapefruit. It is found throughout nature and in thousands of other herbs and plants. It appears in many strains of cannabis, as well as apparently in my friend’s plectranthus amboinicus houseplant.
Limonene is a distinctive and special terpene that does much more than deliver aroma. It also aids in digestion, helps alleviate depression, and contributes anti-bacterial and anti-fungal properties (in this respect, it acts similarly to a cannabinoid). Probably most important, it is also known to fight cancer.
Dissing the Wine Snobs
I recall reading cannabis strain reviews in the past, in which reviewers referred to the aroma of the pot they were sampling as “pine needles with a hint of rosemary” or “very earthy, with coffee undertones and musk” or some such thing.
Just as with fine wines, I discounted most of these olfactory observations, thinking they were mostly the pompous perceptions of subject matter experts who had to find one way or another to turn their reviews into a respectable—and profitable—craft.
But I was terribly wrong. On the surface, it may seem absurd that a strain of cannabis would smell like a completely different species of plant (such as a pine tree, juniper plant, peppermint bush, or lemon tree). But they simply do. More important, the source of that aroma—chemically speaking—is also the same.
Limonene is limonene is limonene, regardless of the plant in which it appears. It is the identical molecule. Ditto for any other terpene found in nature.
Of course, the final mix of terpenes is unique to not only each plant species, but also to each strain or subject. One Durban Poison cannabis plant will produce a unique terpene profile, just as humans sport different voices, intelligence levels, and eye colors.
Myrcene, the most common terpene in cannabis, is also found in basil, mangos, lemon grass, and hops. It conveys earthy, spicy, balsamic, or clove odors and is known to have antimicrobial, antiseptic, antioxidant, and anti-carcinogen effects (several terpenes have been proven to fight cancer).
Pinene, the most common terpene in nature, is available in both alpha and beta varieties. The alpha type conveys a scent of pine needles or rosemary, while the beta smells like parsley, basil, rosemary, dill, or hops. It is also found in many non-cannabis plants. Pinene acts as a bronchodilator, making it helpful for people with asthma and other respiratory ailments. It also increases mental focus and energy.
As I reflected back on that summer, I somewhat smugly smiled at the fact that I had recognized the source of the lime smell in my friend’s plant as limonene.
The sacred herb, cannabis, can be enlightening and teach many things. In this particular case, it taught the source of an alien plant’s aroma. More importantly, this case gives insight into how the entire plant kingdom utilizes chemicals (such as terpenes) and mini manufacturing stations (trichomes) to produce them.
All text and photos, unless otherwise noted, Copyright © 2003-2017 Gooey Rabinski. All Rights Reserved.
Gooey Rabinski is a technical writer, photographer, and compliance documentation specialist for cannabis businesses who has contributed feature articles to magazines and media outlets such as High Times, CannaBiz Journal, MERRY JANE, Emerald Magazine, Grow Magazine, Herb.co, The Kind, Skunk, Cannabis Culture, Whaxy, Heads, Weed World, Green Flower Media, Cannabis Health Journal, Green Thumb, and Treating Yourself.
He is the author of Understanding Medical Marijuana, available on Amazon Kindle.