Here's a closer look at that strange green flower that caught my interest. While adding no color contrast to the arrangement, its odd form added an interesting structural touch.
I asked my sister-in-law, who happens to be a fabulous floral arranger, what that flower was, and she told me that it was an echinacea, deformed by my brother's fondness for spraying Round-up. I know that chemicals can do strange things to plants, but I had never seen this kind of thing. So I went home and posted the picture on the University of Tennessee's Soil Plant Pest Center Facebook page with a question asking about what caused the deformity. Here's their answer:
"This is a disease called aster yellows. It's caused by a phytoplasma; vectored by leafhoppers. Very common on Echinacea. Infected plants are reservoirs of the pathogen and should be removed to slow spread."
I forwarded this information to my brother and sister-in-law, and my brother replied, "so I am exonerated." I replied, "only for this specific incident." I don't think that there is any evidence that Roundup is unsafe, but history has shown us that chemicals thought to be safe can turn out to be otherwise. (Think DDT, BPA, agent orange, etc.) I'm not yet in the "never use" camp, but I like to minimize use of Roundup.
Finally, I want to say kudos to the Soil, Plant Pest Center for being such a valuable source of information. I posted my question on Facebook on a Sunday evening and had an answer less than 5 minutes! While I'm not expecting this speedy service every time, it was an appreciated surprise.