No, it doesn’t have a disease.
Yes, “EWWW” was my first response when I looked underneath the frond and realized I was touching the spots. 🙂
Actually, my fern is fertile. Yay!
The spots under the fronds are called sori (plural). Each sorus (singular) is filled with spores. When there is enough moisture, the spores will release and do their thing in the soil (fertilize itself; each spore contains male and female parts). Hopefully next year I will have more ferns.
Ferns do not produce seed, flower, nor fruit. They, like mushrooms, reproduce by spore. Isn’t that neat! This has been your daily dose of biology class. 😉
Here is a close up photo of the sori.
From on top, you would never know what’s going on underneath. This is my first year growing ferns, I hope to fill the shady spots along my fence will baby ferns.
What do you have growing in your yard?
Let's Paint Nature! 
Hi Christine, I’ve seen these spots on ferns in bouquets from stores. Now I understand. We have ferns in our yard, and peonies soon. Thanks, Ellen
Oh I love peonies! What a huge biggie flower and gigantic fragrance…I can do without all the ants tho…hahaha!
I lived in Washington state for 6 years and the ferns were everywhere. There are so many kinds and I have noticed these small spots underneath as well. I had no idea that they reproduced like mushrooms, how interesting!
Yes, very interesting! I bet Washington state is beautiful, maybe someday I will make it out to the north west. Thanks for commenting 🙂
Love the details in your painting and about the ferns. I love ferns, but don’t seem to have the touch for growing them. They are such a great accent, a little like dropping green lace in the garden
Yes, green lace! I know ferns need a moist and shady spot. Maybe that can help with growing?
We have ferns all over the place, but I can’t take any credit for it. They’re on their own, and they’re better off without my help… : (
But none of them look as appealing as your sketches. Sure wish you’d done the drawings in my old biology textbook– I mighta done better!
Lovely work, Christine, and I liked how you used fern fronds for the bars in the big blue F!! : )
Thanks Mark!!! I don’t think any scientific book would want my drawings…I’m not anal enough and I refuse to count each leaf…being that exact takes all the fun out of art! hahaha!
Your fern is pretty. Are those coleus in the background of the bottom photo?
Yes! I have several coleus (or is it colei???) around, they are so easy to grow, it seems the pests don’t like it and I love the varigated color…pink and green 😀
They do come in brilliant colors, one of my favorites.