—42— 



This is possibly variety concolor of Milde, which was ac- 

 credited to "wet rocks, Niagara Falls, Dr. Engelmann, August, 

 1856," but it does not agree well, and the name is preoccupied. 

 It is a good sub-species, and were it not for the fact that the 

 group is so variable would be entitled to specific rank> 

 Equisetum ScrirpoidES Michx. 



Stems densely cespitose, 10 to 100 in a tuft, naked or slightly 

 branched from base, green, smoothish, very slender, J/£ line in 

 diameter, 2 to 12 (mostly 4) inches long, prostrate or ascending, 

 falsely 6 to 8 carinate, the internodes usually curved or wavy ; 

 carinas mostly 3, rarely 4, broadly concave, equaling the valleculas 

 in width, bearing a regular row of tubercles on each side, other- 

 wise naked ; valleculas with two regular rows of stomata, the 

 cells between bearing scattered rosulas ; sheaths loose, with 3 or 

 4 leaves, green, with a narrow black limb, usually becoming en- 

 tirely black or brown ; leaves with very broad central and lighter 

 lateral grooves, thus being 4 angled. Teeth grooved and black 

 centrally, broadly white bordered, persistent or becoming broken 

 off, not coherent, with more or less persistent subulate points; 

 spikes 2 lines long, of 5 or 6 whorls of sporophyls, black, sessile 

 or slightly exserted from the broad upper sheath, formed in sum- 

 mer and sporiferous the following May. Central cavity absent, 

 the carinas and their bast forming a trefoil at the center ; val- 

 lecular cavities large, often filled with loose parenchyma. Green 

 parenchyma continuous and abundant, the epidermal bast forming 

 a narrow band instead of being accumulated at the carinas and 

 valleculas. 



A very striking plant which is doubtless often overlooked 

 because of its small size and resemblance to fine grasses and 

 carices, with which it is often mixed. It is more readily found 

 in fall and spring when the grasses are brown. The wavy or 

 curved, internodes are very characteristic, the lower being often 

 nearly straight, while the upper bend in a half circle; the tops of 

 the stems being often S-shaped. 



The stems often become prostrate and covered with decaying 

 leaves, when they send out branches similar to themselves. It is 

 the only specie^ where the branches have as many angles as the 

 stem. No other species of the sub-genus lacks a central hole, 

 except Variegatum anceps. 



