Yellow flowers

August 1
On river. — Bidens Bechii.  

Sunflower. 

Meadow-haying begun for a week.  

Hieracium Canadense, apparently a day or two.

H. D. Thoreau, Journal, August 1, 1854

On river. — Bidens Bechii. See August 1, 1859 ("The B. Beckii (just beginning to bloom) just shows a few green leafets above its dark and muddy masses, now that the river is low."); See also A Book of the Seasons, by Henry Thoreau, The Bidens Beckii

Sunflower. See  August 1, 1852 ("The small rough sunflower (Helianthus divaricatus) tells of August heats."); August 1, 1852. ("Helianthus annuus, common sunflower. May it not stand for the character of August? "); August 1, 1855 ("Small rough sunflower a day or two.") See also A Book of the Seasons, by Henry Thoreau, Helianthus

Meadow-haying begun for a week. See August 1, 1860 ("Meadow-haying commenced. ") See also  July 22, 1852 ("Farmers have commenced their meadow-haying"); July 30, 1853. ("In every meadow you see far or near the lumbering hay-cart with its mountainous load and the rakers and mowers in white shirts "): August 5, 1854 ("I find that we are now in the midst of the meadow-haying season, and almost every meadow or section of a meadow has its band of half a dozen mowers and rakers, either bending to their manly work with regular and graceful motion or resting in the shade, while the boys are turning the grass to the sun. I passed as many as sixty or a hundred men thus at work to-day.") and A Book of the Seasons, by Henry Thoreau, Haymaking

Hieracium Canadense apparently a day or two. See July 25, 1856  ("The Hieracium Canadense grows by the road fence in Potter's hydrocotyle field, some seven or eight inches high, in dense tufts!"): August 9, 1853 ("The Hieracium Canadense is out and is abundant at Peter's well"); August 17, 1856 ("Hieracium Canadense.");   August 21, 1851 ("I have now found all the hawkweeds. Singular these genera of plants, plants manifestly related yet distinct. They suggest a history to nature, a natural history in a new sense.") See also A Book of the Seasons, by Henry Thoreau, the Hawkweeds (hieracium)