The river for some days has been open and its sap visibly flowing, like the maple.

February 21. 

The puffball is used by doctors to stop bleeding. Has not this property to do with its power of repelling moisture? Some have now almost entirely lost their dust, leaving a dry almost woolly substance. 

Am surprised to see this afternoon a boy collecting red maple sap from some trees behind George Hubbard's. It runs freely. The earliest sap I made to flow last year was March 14th. It must be owing to the warm weather we have had. 

The river for some days has been open and its sap visibly flowing, like the maple.

H. D. Thoreau, Journal, February 21, 1857
The puffball . . . its power of repelling moisture. See February 8, 1857 ("Though it is but just brought to light from beneath the deep snow,. . . it is just as dry and dusty as ever . . .. It was impossible to wet. ")

Am surprised to see this afternoon a boy collecting red maple sap from some trees behind George Hubbard's. It runs freely. See February 23, 1857 ("I have seen signs of the spring. . . .. I have seen the clear sap trickling from the red maple."); March 3, 1857 ("The red maple sap, which I first noticed the 21st of February, is now frozen up in the auger-holes .");  March 28, 1857 ("The maple sap has been flowing well for two or three weeks. ); see also  March 4, 1852 (I see where a maple has been wounded the sap is flowing out. Now, then, is the time to make sugar."); March 5, 1852 ("As I sit under their boughs, looking into the sky, I suddenly see the myriad black dots of the expanded buds against the sky. Their sap is flowing.”); March 7, 1855 ("To-day, as also three or four days ago, I saw a clear drop of maple sap on a broken red maple twig, which tasted very sweet.") March 24, 1855 ("It is too cold to think of those signs of spring which I find recorded under this date last year. The earliest signs of spring in vegetation noticed thus far are the maple sap, the willow catkins, grass on south banks, and perhaps cowslip in sheltered places. Alder catkins loosened, and also white maple buds loosened.");

The earliest sap I made to flow last year was March 14th. See March 14, 1856 ("Tapped several white maples with my knife, but find no sap flowing; but, just above Pinxter Swamp, one red maple limb was moistened by sap trickling along the bark. Tapping this, I was surprised to find it flow freely. . . . "); March 15, 1856 ("Put a spout in the red maple of yesterday, and hang a pail beneath to catch the sap")

The river for some days has been open. See February 17, 1857 ("Thermometer at 1 p.m., 60°. The river is fairly breaking up, and men are out with guns after muskrats, and even boats.") See also  February 12, 1860 ("That dark-eyed water, especially when I see it at right angles with the direction of the sun, is it not the first sign of spring?"); February 20, 1855 ("I see from my window the bright blue water here and there between the ice and on the meadow."); February 27, 1852 ("The main river is not yet open but in very few places, but the North Branch, which is so much more rapid, is open near Tarbell's and Harrington's, where I walked to-day, and, flowing with full tide bordered with ice on either side, sparkles in the clear, cool air, . . .  If rivers come out of their icy prison thus bright and immortal, shall not I too resume my spring life with joy and hope ?")