Gossamer. I was driving eastward on Cruzon Grade in Nevada County, facing the morning sun. It must have been in the fall. As I understand it, that's Gossamer Season.
Gossamer, as in gossamer wings or the fabric of Lady Caro Lamb's dresses, has the reputation of being sheer, elegant and flimsy. Sheer and elegant to be sure, but never flimsy. Gossamer is spider web and there is no natural substance with a greater tensile strength.
There comes a time in every young spider's life when he has a choice. Leave home or become dinner for mama. (This is a choice she spiders must make, also, since mama is an equal opportunity diner.) The young spiders seek out the highest point they can find, even if it's only on top of a flower or a blade of grass. Then he squirts out some streams of silk from some of his spinnerettes, and they harden as soon as they are exposed to air. The strands become “wings” to carry the baby spiders away from their ravenous mothers.
The young Cruzon Grade spiders are fortunate because they don't have to launch themselves from flowers or grass blades. They have cedars 60-, 70-, 80-, 100-feet tall, all an escaping baby spider could wish for. A couple of squirts, and they're aloft, going wherever the wind takes them. (They don't have much control over where they go, and I imagine some of them end up in the middle of a river or a lake.)
On this particular day there were thousands of those little guys making an arachnid exodus. The breeze was just enough to keep them aloft, but not enough to take them anywhere. The morning sun shone through the silk shrouds and acted as a crystal. The light rays separated and the spider silks became a curtain of shimmering rainbow colors.
And so I found what was at the end of the rainbow. Well, under the rainbow. Thousands of spiders. Who knew.