Abundant fine and light seed, buoyed up and wafted far through the atmosphere.

May 20. 

A strong, cold west wind. 60° at 2 P. M. 

To Walden. 

The Carex vulgaris is more glaucous than the stricta.

Mouse-ear down at last. 

Scirpus planifolius — how long? — apparently in prime in woods about the bottom of the long south bay of Walden, say two rods southwest. 

Judging from Hind's Report of his survey of the region between the Assiniboine and Saskatchewan Rivers, the prevailing trees — and they are small — are aspens and willows, which, if let alone, i. e., if the prairies were not burned by the Indians, might at last make a soil for nobler forests. 

No wonder that these small trees are so widely dispersed; their abundant fine and light seed, being buoyed up and wafted far through the atmosphere, speedily clothe the burnt tracts of British America. Heavy-seeded trees are slow to spread themselves, but both air and water combine to transport the seeds of these trees.

H. D. Thoreau, Journal, May 20, 1860

The Carex vulgaris is more glaucous than the stricta. See May 10, 1860 ("A sedge darker than the stricta and not in tufts, quite short. Is it the C. vulgaris? Its leading spikes are effete. ")

Scirpus planifolius  apparently in prime. See May 11, 1859 ("Scirpus planifolius in bloom on Smith's wooded hill, side of Saw Mill Brook.")

Mouse-ear down at last. See May 26, 1855 ("Already the mouse-ear down begins to blow in the fields and whiten the grass.")

No wonder that these small trees are so widely dispersed, See  December 30, 1855 ("For a few days I have noticed the snow sprinkled with alder and birch scales. . . .The high wind is scattering them over the snow there."); February 14, 1856 ("I was struck to-day by the size and continuousness of the natural willow hedge on the east side of the rail road causeway, at the foot of the embankment, next to the fence. Some twelve years ago, when that causeway was built through the meadows, there were no willows there or near there, but now, just at the foot of the sand-bank, where it meets the meadow, and on the line of the fence, quite a dense willow hedge has planted itself. [T]he seeds have been blown hither from a distance, and lodged against the foot of the bank, just as the snow-drift accumulates there. "); March 2, 1856 ("How unwearied Nature is, spreading her seeds.");  May 26, 1857 ("Some of the earliest willows about warm edges of woods are gone to seed and downy"); July 9, 1857 ("I think I see how this [willow]tree is propagated by its seeds. Its countless minute brown seeds, just perceptible to the naked eye in the midst of their cotton, are wafted with the cotton to the water, — most abundantly about a fortnight ago, — and there they drift . . ."); October 16, 1860 (Looking from a hilltop, I observe that pines, white birches, red maples, alders, etc., often grow in more or less regular rounded or oval or conical patches, while oaks, chestnuts, hickories, etc., simply form woods of greater or less extent, whether by themselves or mixed, and do not naturally spring up in an oval form. This is a consequence of the different manner in which trees which have winged seeds and those which have not are planted")