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Staggerbush (Lyonia) leaf galls
Exobasidium sp.
Today’s topic comes from Chase Robertson, correspondent from Jonathan Dickinson State Park scrublands. Take a walk there or in other scrub, especially after fire maybe, and marvel at big reddish fleshy flowery-looking things on the Staggerbushes.
Photo by John Bradford
They remind me of that infamous mouse with a “human ear.” Maybe we could start engineering crops with human body parts. Ha ha.
The Staggerbush galls are the funny business of a fungus Exobasidium (probably E. ferrugineae). There are about 50 Exobasidium species altogether, and they have a special preference for members of the Blueberry Family, including Lyonia.
Photo by John Bradford
They also are pests on Tea.
The fungus is in the same fungal kingdom as mushrooms in which the mushroom cap serves to drop spores onto the wind. Exobasidiums don’t have a cap, instead they transform the host leaf into one. Fungal strands grow out through the leaf stomates and release spores all over the surface of the leaf. Look at the following photo showing the threadlike fungal strands spreading across the deformed leaf, and spores beginning to appear.
By JB
Speaking of revealing photos, look at the one below by Chase Robertson, showing a fly on the gall. Let us now speculate. Flies pollinate flesh-colored flowers as well as some flesh-colored fungi, including at least one other species of Exobasidium. The Exobasidium galls on Staggerbush have that carrion color attractive to flies. Do the flies then disperse the spores around the habitat to other plants? Don’t know…but my bet is on yes.
Treasure Coast Natives 