in Thoreau’s Journal:

The first really cold day. I find, on breaking off a shrub oak leaf, a little life at the foot of the leafstalk, so that a part of the green comes off. It has not died quite down to the point of separation, as it will do, I suppose, before spring. Most of the oaks have lost their leaves except on the lower branches, as if they were less exposed and less mature there, and felt the changes of the seasons less. The leaves have either fallen or withered long since, yet I found this afternoon, cold as it is, – and there has been snow in the neighborhood, – some sprouts which had come up this year from the stump of a young black-looking oak, covered still with handsome fresh red and green leaves, very large and unwithered and unwilted. It was on the south side of Fair Haven in a warm angle, where the wood was cut last winter and the exposed edge of the still standing wood running north and south met the cliff at right angles and served for a fence to keep off the wind. There were one or two stumps here whose sprouts had fresh leaves which transported me back to October. Yet the surrounding shrub oak leaves were as dry and dead as usual. There were also some minute birches only a year old, their leaves still freshly yellow, and some young wild apple trees apparently still growing, their leaves as green and tender as in summer. The goldenrods, one or more species of the white and some yellow ones, were many of them still quite fresh, though elsewhere they are all whitish and dry. I saw one whose top rose above the edge of a rock, and so much of it was turned white and dry; but the lower part of its raceme was still yellow. Some of the white species seemed to have started again as if for another spring. They had sprung up freshly a foot or more, and were budded to blossom, fresh and green. And sometimes on the same stem were old and dry and white downy flowers, and fresh green blossom-buds, not yet expanded. I saw there some pale blue asters still bright, and the mullein leaves still large and green, one green to its top. And I discovered that when I put my hand on the mullein leaves they felt decidedly warm, but the radical leaves of the goldenrods felt cold and clammy. There was also the columbine, its leaves still alive and green; and I was pleased to smell the pennyroyal which I had bruised, though this dried up long ago. Each season is thus drawn out and lingers in certain localities, as the birds and insects know very well. If you penetrate to some warm recess under a cliff in the woods, you will be astonished at the amount of summer life that still flourishes there. No doubt more of the summer’s life than we are aware thus slips by and outmanoeuvres the winter, gliding from fence to fence. I have no doubt that a diligent search in proper places would discover many more of our summer flowers thus lingering till the snow came, than we suspect. It is as if the plant made no preparation for winter.