The horse-chestnut and mountain-ash leafing.

May 6. 

To Clamshell by river. 

Our earliest currant out. 

Oat spawn showing little pollywogs (?) in meadow water. 

The horse-chestnut and mountain-ash leafing.

Knawel out at Clamshell; how long? 

Cerastium out there under the bank. 

That early white birch there has about done running sap. 

Equisetum sylvaticum a day or two on the ditch bank there.

H. D. Thoreau, Journal, May 6, 1856

Our earliest currant out. See May 4, 1853 ("The currant in bloom"); May 4, 1860 ("Currant out a day or two at least."); May 9, 1854 ("Currant in garden, but ours may be a late kind."); May 9, 1855 ("The black currant will not bloom for five or six days.")  

Note: The "earlies currant" and the unqualified word "currant" in Thoreau's lexicon likely  refers to the commonly cultivated Red Currant (Ribes rubrum). The Currant family species in New England includes both currants and gooseberries:   

• Ribes americanum –Wild black currant f/k/a Ribes floridum. See May 8, 1853 ("The Ribes floridum, wild black currant, just begun")
• Ribes aureum – Golden currant 
• Ribes cynosbati –Prickly gooseberry. See  September 8, 1856 (" Prickly gooseberry, with its bur-like fruit")
• Ribes glandulosum Skunk currant, fetid currant f/k/a Ribes prostratum. See September 7, 1852 (“Wild currants (Ribes prostratum, with the berry the odor of skunk-cabbage, but a not quite disagreeable wild flavor.")
• Ribes hirtellum –  Hairy stem Gooseberry or Northern Gooseberry 
• Ribes lacustre –Prickly currant, swamp gooseberry, bristly black currant. See June 19, 1856 (at the Natural History rooms)("Ribes lacustre, or swamp gooseberry")
• Ribes missouriense –Missouri gooseberry or Missouri currant. See  May 5, 1855 ("Missouri currant look as if they would bloom to-morrow.”);
• Ribes nigrum – Black Currant. See May 18, 1856 (“R. W. E.’s black currant (which the wild Ribes floridum is said to be much like), maybe a day.”)
• Ribes rotundifolium –Appalachian gooseberry or round-leaved gooseberry
• Ribes rubrum  – garden red currant or red currant
• Ribes triste –swamp red currant or wild red currant
• Ribes uva-crispa – European gooseberry f/k/a Ribes grossularia

Thoreau recognized 6 kinds of currant: red currant, black currant, wild currant, wild black currant, swamp currant, and Missouri currant; and 2 kinds of gooseberry,  swamp gooseberry and prickly gooseberry. See May 5, 1855 ("Gooseberry, both kinds ");See also, e.g.; July 19, 1858 (Mt. Washington) (" At three miles, or limit of trees . . . Ribes lacustre, prostratum, and floridum(?)") 

Oat spawn showing little pollywogs. See May 4, 1858 (“What I have heretofore called the oat spawn, attached to old pontederia stems,  etc . . . is not black and white, like that of the Rana halecina, sylvaltica, and palustris, which I cannot distinguish from one another, but a pale brown or fawn-color . . . Iss it not that of the R. fontinalis?”);  May 8, 1858 (“I see a great deal of the oat spawn . . . It is over the coarse, weedy (pontederia and yellow lily stubble)”); May 11, 1855 (“See oat-seed spawn — a mass as big as fist —- on bottom; of brown jelly composed of smaller globules, each with a fish-like tadpole, color of a seed.”);  May 13, 1858 ("The large globular masses of oat spawn, often on the very top of the old pontederia stems and also on the shooting Equisetum limosum, of the same color with the weeds and bottom, look like a seedy fruit which is divested of its rind."); May 13, 1857 ("A large bunch of oat spawn in meadow water.“)

The horse-chestnut and mountain-ash leafing. See May 5, 1855) ("The trees and shrubs which I observe . . . in the order of their intensity and generalness: Gooseberry, both kinds  . . . Red currant, and probably black . . .  Some mountain-ash . . . Some horse-chestnut")

Knawel out at Clamshell; how long?  See May 5, 1860 ("Knawel some time."); May 6, 1853 ("Common knawel, apparently for some time") [Scleranthus annuus (German knotweed)]

Cerastium out there under the bank. See  May 13, 1860 ("At Clamshell. one cerastium flower quite done and dry."); See also  May 22, 1856 ("A little clammy hairy cerastium (?) ( like a Cerastium viscosum, slender and erect ), about three inches high, will open in a day or two on the rock near the"); May 31, 1856 ("That little cerastium on the rock at the Island, noticed the 22d, which probably opened about that time, is now out of bloom.")

That early white birch there has about done running sap. See April 23, 1856 ("The white birch sap flows yet from a stump cut last fall, and a few small bees, flies, etc., are attracted by it.");  April 26, 1856 ("The white birch at Clamshell, which I tapped long ago, still runs and is partly covered with a pink froth. "); April 27, 1856 ("The white birch which I tapped in V. palmata Swamp still runs; and the holes are full of, and the base of the tree covered with, a singular sour-tasted, rather hard-crusted white (not pink) froth, and a great many of those flat beetles (?), lightning-bug-like, and flies, etc.  are sucking it."); May 13, 1856 ("Where my sap has dried on the white birch bark it has now turned a bright light red. What a variety of colors it assumes!")

Equisetum sylvaticum  [Wood horsetail or Woodland horsetail] a day or two on the ditch bank there. See   May 6, 1853 ("Equisetum sylvaticum in front of Hosmer's Gorge. ");  May 6, 1855 ("Equisetum sylvaticum, probably yesterday or day before.”);  See also April 28, 1858 ("At Clamshell Ditch, one Equisetum sylvaticum will apparently open to-morrow. Strawberries are abundantly out.); May 10, 1857 (“This side Clamshell, strawberries and cinquefoil are abundant. Equisetum sylvaticum.”)