Oh, no! What are those tiny opaque dots on the back of my Cissus amazonica? Does it have bugs?!
My first reaction was bugs of course until I looked closer. I was immediately angry, thinking this newer plant had bugs from the greenhouse. You may think so, too when you first see these small dots on the back of your plant. You may even reach for some sort of bug killer whether it be insecticidal soap or insecticide. But, before you do, let’s look a bit closer at these small dots.
You’ll be happy to know these aren’t bugs but are cystoliths. Cysto-what? Cystoliths. What are those? I’ll be honest. I’m still not exactly sure what they are or what they do, but I do know they aren’t bugs. They are calcium carbonate crystals on cell walls in the epidermis of the plant. I did read that calcium carbonate CaCO3, is also found in limestone, eggshells, and pearls. Interesting, right? Here is an article with more technical information for inquiring minds here. I am not a scientist, but it is interesting.
The cystoliths do not appear on the front of the C. amazonica leaves, but only on the backs.
Other Members of the Family
I have both Cissus rhombifolia and C. rhombifolia ‘Ellen Danica’, as well (below) and neither of those have the cystoliths on their leaves. Though they can be on other plants in the Vitaceae family, they aren’t on these two relatives. Why on some and not on others? I have no idea.
Other Plant Families with Cystoliths
Cystoliths also appear in other plant families, including Urticaceae (nettle), Ulmaceae (elm), Acanthaceae (acanthus), Cucurbitaceae (gourd), and the Moraceae (fig/mulberry) family which includes figs and rubber trees. My Ficus elastica ‘Burgundy’ and F. elastica ‘Tineke’, and the Ficus benghalensis ‘Audrey’ below all have cystoliths present. I did look at my other ficus plants and I didn’t see any on the fiddle leaf, Ficus lyrata, Ficus benjamina, or my variegated Ficus maclellandii ‘Alii’. They may be there but aren’t as obvious as the ones on the rubber plants. The rubber trees do have much thicker leaves and so maybe that has something to do with it….? I also read that those cystoliths scatter the light around inside the cells of these plants, as well.
The fiddle leaf fig below doesn’t show any signs of cystoliths.
The Point Is…..
The point of this blog post is to show you that some things aren’t as they seem. Though these small dots look like bugs, they aren’t. So you have nothing to worry about as they are a natural part of the leaves. I hope you feel better now if you’ve noticed these small dots on your plants’ leaves and panicked as I did.
Have a great week, plant friends!