in Thoreau’s Journal:

Returning, I see the red oak on R. W. E.’s shore reflected in the bright sky water. In the reflection the tree is black against the clear whitish sky, though as I see it against the opposite woods it is a warm greenish yellow. But the river sees it against the bright sky, and hence the reflection is like ink. The water tells me how it looks to it seen from below. I think that most men, as farmers, hunters, fishers, etc., walk along a river’s bank, or paddle along it stream, without seeing the reflections. Their minds are not abstracted from the surface, from surfaces generally. It is only a reflecting mind that sees reflections. I am aware often that I have been occupied with shallow and commonplace thoughts, looking for something superficial, when I did not see the most glorious reflections, though exactly in the line of my vision. If the fisherman was looking at the reflection, he would not know when he had a nibble! I know from my own experience that he may cast his line right over the most elysian landscape and sky, and not catch the slightest notion of them. You must be in an abstract mood to see reflections however distinct. I was even startled by the sight of that reflected red oak as if it were a black water-spirit. When we are enough abstracted, the opaque earth itself reflects images to us; i. e., we are imaginative, see visions, etc. Such a reflection, this inky, leafy tree, against the white sky, can only be seen at this season.

It is very pleasant & cheerful now days—when the brown & withered leaves strew the ground—& almost every plant is fallen or withered—to come upon a patch of polypody (as in abundance on hill side between Calla swamp & Bateman’s P.) on some rocky and still more (same) hillside E of the Callas hill side in the woods—  When in the midst of dry & rustling leaves defying frost it stands so freshly green & full of life—The mere green which was not remarkable in the summer—is positively interesting now— My thoughts are with the poly-pody a long time after my body has passed. The brakes—the sarsaparilla—the Solomons seals—the ladies slippers—the osmundas—have long since withered & fallen. — The huckleberries & blueberries too have lost their leaves—  The forest floor is covered with a thick coat of moist brown leaves, but what is that perennial & spring like verdure that clothes the rocks—of small green plumes pointing various ways— It is the cheerful community of the polypody. It survives at least as the type of vegetation to remind us of the spring which shall not fail. These are the green pastures where I browse now— Why is not this form copied by our sculptors instead of the foreign acanthus leaves & bays? 

The sight of this unwithering green leaf excites me like red at some seasons.  Are not wood frogs the philosophers who walk in these groves? —Methinks I imbibe a cool composed frog-like philosophy when I behold them. I don’t care for acanthus leaves— They are far fetched— I do love this form however— & would like to see it whether on your marble or my butter painted or sculptured — How fit for a tuft about the base of a column….

The evergreen ferns & lycopodiums— now have their day—now is the flower of their age—& their greenness is appreciated. They are much the clearest & most liquid green in the woods—more yellow & brown specked in the open places— The form of the polypody is strangely interesting—it is even outlandish. Some forms though common in our midst are thus perennially foreign as the growths of other latitudes—there being a greater interval between us & their kind than usual. We all feel the ferns to be further from us essentially—& sympathetically—than the phaenogamous plants—the roses & weeds for instance— It needs no geology nor botany to assure us of that—we feel it—& told them of it first. The bare outline of the polypody—thrills me strangely—it is a strange type which I cannot read—It only piques me— Simple as it is, it is as strange as an oriental character. It is quite independent of my race & of the Indian— & all mankind. It is a fabulous mythological form—such as prevailed when the earth & air & water were inhabited by those extinct fossil creatures—that we find. It is contemporary with them and affects as the sight of them.