The Sun and Fog contested — Sun-fern

The Sun and Fog contested 1
The Government of Day-
The Sun took down his Yellow Whip
And drove the Fog away-
(F.1248/J.1190)
[1] Sun: sun-fern, a plant with whip-shaped unrolled brown fronds. Fog: a general name for moss in Scotland. "Lime is the mortal enemy of all sorts of fog or moss (OED n.1 2)."
[2] Government of Day: control of the ground; control of the nation.
[3] Whip: shape of the sun-fern; a hint on the Whig party.
[4] drove, away: sun-fern prefers sunshine but the moss not.

In English it is known as the Pale Mountain Polypody, Mountain Polypody, and Sun Fern, names referring to the high and fully-exposed-to-the-light situations in which it delights. . . . Fronds scattered, erect, five to eighteen inches high, sharp-pointed, spear-head shaped, delicate-textured, covered with small hairs.——The British Ferns (1857)