I'd been waiting for a morning just like this: clear and still and cold enough for a good hard frost. We had a dusting of snow in Saratoga Springs, but when I arrived at Mud Pond in Moreau, I was pleased to see that no snow had fallen to obscure the frothy curls of frozen sap exuded from the stems of the Frostweed (Helianthemum canadense) that grows prolifically there along a sandy path.
In June, and once again in August, Frostweed bears yellow flowers that are pretty enough but easily overlooked or undiscovered, since they're small and bloom for only a day or so. What really sets this native plant apart are the icy curls that form at the base of its wiry stems during the first few days of freezing temperatures in late fall. These curls are formed when the stems split lengthwise as they freeze, allowing the plant's sap to ooze out, freezing hard in the frigid air. This phenomenon occurs for only a few days, until the plant's sap is spent and the roots freeze. I missed this event last year, so I was really happy to find the process in full swing this morning. I was able to take lots of photos.
I was sure to arrive at this site before the sun rose high enough to warm the plants and melt the frothy ice. Ten minutes after I took this photo, the Frostweed curls had disappeared.