In yesterday night's blog entry I mentioned some Pale Touch-me-not that was wilted, and speculated that it could be due to the hot, relatively rain-free conditions. I was exploring Cedar Creek Park (near Donora) today and saw something that makes me think that the plants 'wilt' due to heat or direct sunlight but not due to lack of water.
I found a plant that was half in the sun and half in the shade. The sunny side (on the right) had 'wilted' curled up leaves and the shady side (on the left) did not! Since the plant gets all its water from the same root system (and also because it had recently rained in that area), it is very unlikely that the plant was wilting on only one side due to lack of water. Instead, it is probably curling its leaves to reduce the effects of heat and sunlight.
There were many other plants in direct sun, which were also 'wilty', and in shade, which were not.
I'll have more thoughts on my visit to Cedar Creek Park soon!