or with simple or compound, verticillate, branches in 
others. Leaves rudimentary, verticilhite, united nearly 
their entire leng^th forming: sheaths at the nodes of the 
stem. 
t Stems of one kind, 
* Annual species, 
i. Effluviatile L. 
Eqitisetum fluviatile L. Sp. PI. 1062. Underw , 
in 111. Fl. I :37 ; Nat. Ferns 128 ; in Britt. Man. 
23. Clute^ Fern Allies 58. 
E. limosum L. 1. c. Eaton,^ in Gray, Man. 677. 
Pipes. 
Plants 6- 1 2 dm. or higher ; sterile stems 6 mm. or 
wider at the base, tapering gradually, with numerous 
slender, simple, smooth branches; fertile stems similar, 
bearing oblong-ovate, 2 cm. 1., i cm. wide spikes; the 
branches develop after fructification, 
In shallow waters and swamps. 
Reported from Virginia by one of the earlier botanists. I have 
seen no specimens from stations south of Pennsylvania. 
E, limosum is apparently only a simpler form of E, 
fluviatile having but few branches. It was described by 
H a r t m a n as E, fluviatile ^ limosujn, [Skand. Fl. 
ed. 10. 286. 1870, and in earlier editions. ] 
59 
