or 
of 
AMERICAN FERN JOURNAL 
the — cavity only one-half to one-third the diameter 
the internode. 
1. Stem vith central cavity, agua a sheath seg- 
ments usually quadricari 
2. Stem solid, mostly erat uchiha prenee) sheath 
II. Con 
segments somewhat quadricarinate. . scirpoides. 
es rounded at the top or merely acute, not st a rigid point; 
aerial stems annual, not surviving the winter in regions of frost. 
A. Aerial stems all green and essentially alike. 
1. Fertile stems usually not branched above ground but some- 
F 
o 
times developing whorls of minute branches while the cones 
are maturin g; stems with cross bands of silex; plants of dry 
or ordinary pcos 
Not with numerous branched basal sterile shoots around 
the fertile shoots; stems very smooth, with cross bands of 
silex; limb of the long green sheath dilated upward, with 
a narrow black band at the top, not incurved. £. kan- 
sanu 
; With ¢ a gor or rosette of small, Ss sterile shoots 
around the base of the fertile shoots; stems very rough 
with cross bands of silex; limb of #08 rather short sheath 
strongly ineurved with age, with a narrow sie band at 
the top; stomata often in two rows. E. 
nston 
2. Fertile stems branched, usually with numerous “whorl of 
branches; plants of wet soil or growing in the wat 
b. 
B. Aerial fet : two kinds, the sterile shoots green and much 
és Sheathe usually het neem 1 Ya-3 ft. “high, usually 
many-grooved, wi 
E. fluviatile. 
Sheathe. loose and somewhat dilated; stems 14-1)4 ft. 
Poe ~~ 5-10-grooved; central cavity rather small. 
branched, the fertile brown and at least at first with little or no 
ophy 
chlor 
Beta haus producing branches after the maturity of the 
ring. 
a. 
b. 
spores, -~. the pu whe 
Branches 
downwar ra E. silvaticu 
Branches of the = pie fertile shoots simple and 
straight. £, 
ind, curved 
pra 
2. Fertile shoots withering pitas the spores are shed, rarely pro- 
ducing branches 
~~ 
oS aks a a 
ea ae § i 
