Nancy G. wrote:
Bruce Musgrove wrote:
Could this be a burn mark from water sitting on the leaf in
the sun?


Probably. When the leaves fall in my area, it changes the light
intensity through the sunny windows. A drop of water, in this case oil
from the soap will scald the leaves because it acts like a lens and
concentrates the light more..................

I have never believed that this happens, at least not with water. I
don't believe the part of a leaf under a drop of water can possibly get
hotter than the adjacent areas. Sort of an urban legend. Perhaps a
suburban legend, in this case, since I have seen the same reasoning in
reference to watering lawns while the sun is shining. (There may be
other good reasons to avoid watering lawns while the sun is shining, but
I don't believe in the lens theory.)

Steve
PS Nancy, your other advice is great and I always appreciate your in
depth answers.