Scents and odors

This is just for fun: do you have any memories of making an observation with a distinct smell? Not long ago, I made an observation of a red deadnettle.

I’d never seen any before, and originally thought it was some kind of mint, so I picked some and took a good whiff… It was pungent to say the least. I may not even have taken a picture if it hadn’t been for the unpleasant surprise I got when expecting a nice sharp minty fragrance.

On the more pleasant side, I can remember many occasions of following my nose to California Bay, Blue Gum Eucalyptus, sage, etc. Sometimes I wish we could upload smells with our observations. Other times I remember what a terrible idea that would be :sweat_smile:


i like to smell different plants, especially leaves of mint family members. it’s also interesting to guess what a flower will smell like based on what kind of insects are hanging out on it. seems like beetles and flies like flowers that most of us would consider stinky (ex. cheesy smells), while bees and butterflies tend to go after flowers that i would consider more floral.

once i broke off a leaf of a very robust Aloe vera plant that was in bloom, and the goo inside was super viscous, and it smelled just like chicken soup.


I found a beautiful Xystodesmidae millipede that was striking pink and black, it smelled like vanilla/almond! Of course, this was actually just its cyanide gas


I sniff all plants, much to the amusement of other people nearby. Often they ask me, “So what’s it smell like?” and not being very good at describing, usually I have to joke “smells like plant.” It helps me with ID, if I sniff something enough times to remember. Although, no one who asks “what is that?” is impressed by a reply “I don’t know, but it smells like Anacardiaceae.”


Before the pandemic started, I had planned to take a trip to Sequoia National Park. They have several species of millipede (genus Motyxia) there that also produce cyanide and glow in the dark to boot! I’m hoping the park will be open again before the snow comes back and I’ll be able to go see them!


The main distinguishing feature of some fungi – which aren’t morphologically very different from each other – is scent. But people often have a terrible time articulating what they are smelling, and I think a lot of it has to do with culture – English is such a bad language for describing scents!

Example: at a mycological event in the fall, someone collected a mushroom that smelled very strongly of fenugreek. It smelled so strongly of fenugreek that I noticed the smell when I was walking by the table where it was and smelled each of the mushrooms in turn to determine which one it was – it clearly hadn’t been there the night before (it was collected during a morning foray). This particular mushroom was parasitized by another fungus, so it was not easy to tell what it was from its morphology. Also, it was not easy to tell what the parasitic fungus was because it was uncommon and the descriptions all 4 people involved in determining what it was were able to find were terse and not particularly helpful. At the end, we ended up not being able to resolve what was going on, because what I identified unambiguously as a fenugreek smell was identified by one other person as fenugreek but by two others as maple syrup. The fifth person brought in as a tiebreaker called it “spicy.” I suspect that most of the people who write mushroom IDs are not necessarily great chefs (or wine connoisseurs, or perfumers), so there’s a bit of ambiguity in the descriptions of the mushroom we thought it was, as well: some said it smells like fenugreek, some maple syrup, some “spicy and fragrant,” etc. (Fenugreek is used in fake maple syrup but real maple syrup does not smell like fenugreek. The chemical in question is sotolone, which is not in real maple syrup).

(I think that the mushroom that was parasitized was probably Lactarius helvus, the maple syrup milky cap – but it does not smell like real maple syrup, so I find the name annoying).


Haven’t posted them to iNat because I know there’s no way for someone to confirm my ob other than on faith I know what I’m doing- most seabird burrows I’ve worked can be IDed by scent, especially parsing the kororā-little penguin and о̄i-grey faced petrel burrows. Would never wish either of those scents on an innocent iNat identifier :stuck_out_tongue_winking_eye:

It’s the main way we find kororā burrows in dense vegetation and has led to us discovering some previously unknown kuaka-diving petrel colonies as well, with their almost sweet, musty scent catching my nose as walking by on completely unrelated business!


I love this thread. I’ll have to take some time to smell plants more often. Never thought about approaching guessing what smells flowers give off the way @pisum suggested, I have to give that a try and see what I learn over time! Now that I think about it I’m not even quite sure how different insects are attracted to various substances… I’m curious, I’ll have to look into that :)

Stinkhorns are the first to come to mind for me. Here’s an observation I made of an intensely foul-smelling column stinkhorn that blew me away when I bent over to smell it out of curiosity

Ladybugs have a distinct smell as well… last night a ladybug landed on me and although I couldn’t see it I could smell that that’s what it was. I’ve often wondered if other beetles have scents as strong as ladybugs but so far I haven’t detected something like that.

One time I smelled something strange in a garden bed while weeding and searched around in the pinestraw until I found… a garter snake! Which apparently give off a foul-smelling musky odor when threatened.


Sometimes I automatically think “I need to take a picture of that smell!” before realizing that that is not currently technically possible.

Some day I will be able to capture the smell of ponderosa pines in the summer and upload it here, and to Instagram, but not yet!


I sniff Yerba Buena as it’s distinctive lemon/mint smell helps confirm that’s what it is and not a similar looking vine; and I love the smell.


That chemical or some derivative of it must be somewhat common in Lactarius mushrooms. Candy caps (L. rubidus) grow in some of the areas I visit often. I have yet to find one myself, but some people think they smell like curry spices and others say maple syrup. It may not just be that the language is insufficient, though. The actual perception of the scent can vary strongly from person to person.

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I like Yerba Buena, too. Yerba Santa also has a nice smell.

I smell everything that does not get away from me. Some plants I particulary love the scent, I rob a small piece between my hands to release the organic volatile compounds and then take a good whiff. Red elderberry has a distinctive, ei stinky scent. Once you smelled it, you wont forget it.


Many carabids and tenebrionids give off distinctive defense odors, and so do some hemipterans.

I recently caught a brown hemipteran (Brochymena?) which produces the same distinctive poisonous-smelling but sweet scent as almond soap (soap does not smell like snack almonds, presumably those have no benzaldehyde or something).

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There is Mexican Tea, Dysphania ambrosioides. When you crush a leaf of a well-grown plant it has a very distinctive odor, which one of my iNat friends says smells like mint and gasoline – he’s right, though his description made me laugh. The very young plants don’t have that smell – it develops as they get bigger and stronger.

Red foxes when they have crossed my path, they leave behind a smell like nasty smelly feet mixed with a nice smell of fresh-ground black pepper.

Sweet Annie, Artemisia annua, when you crush a leaf it has a lovely warm fragrant smell – Daniel Atha of NYBG taught me that.

And Tree-of-Heaven has a weird strong “green” smell, which most people find quite unpleasant, although some people think it smells a bit like peanut butter.

And skunk smell, when very far in the distance, smells quite good to me.


Does anybody else notice that some green lacewings have this weird gasoline smell? I think about every one I’ve had at my lights have it.


In the short walk from my home to the grocery store there is a row of the invasive Ligustrum sinense trees in flower, and yes they smell very nice.

I distinctively remember the smell of a Menecles insertus stinkbug I found as being quite different from Halyomorpha halys; the former’s spray has a very pungent almondy scent.

Interestingly enough there was a long long time period where I have not eaten cilantro and when I finally brought a bunch and was chopping them up the intense aroma instantly reminded me of the stench that Halyomorpha halys would emit. So it was pretty weird that I associated the smell of cilantro with that of said stinkbug rather than the other way around. I still don’t mind cilantro though.


Some people think cilantro smells or tastes like soap (I used to–now I don’t). This article says the taste of soap or stinkbugs in cilantro is linked to a certain gene in some humans–


that’s interesting. i’ve never noticed a smell from a lacewing, but maybe i’m just not getting close enough? i would not have thought such insects have a smell… i’ll have to try to smell one one day without inhaling the whole insect.


Yup. And where I lived, add some skunk smell to that. You can definitely tell when they’re around, lol.

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