Ee : ‘ 
Gy 0 Stems with fewgseveral whorls of branches (E, fluviatile seldom ae 
@ 4 branched) 
f Branches again branched at maturity, more or less distinctly 
“b recurving, feathery and delicate le E. sylvaticum 
4 Branches unbranched, spreading or ascending 
“ Principal sheaths of sterile shoots 4-8 mm, long; teeth 
8 with indistinct or no hyaline-scarious margin 2. E. arvense 
4 Principal sheaths of sterile shoots 12-15 mm, long; teeth 
a distinct white or silvery hyaline-scarious 
margin Se Ee palustre 
O Stems without branches (E, fluviatile seldom branched) 
2 Stems stout, 7-8 mn, in diam.; teeth of all but uppermost 
ai early deciduous; sheaths prominently black and 
white banded 4. KE, hyemale 
2 Stems slender, 2-5 mm, in diam,; teeth all persistent; sheaths 
qi & black or green and black, tut not strongly banded 
¢ Branches 2 mm, in diam., in more or less tufted clumps; 
8 sheaths black, conspicuous Se Ee. variegatum 
4 Branches 4-5 ma, in diam., simple or few, not tufted; 
& sheaths mostly green, inconspicuous 6. E. fluviatile 4 
simple from a slender rootstock, 30-50 cm, tall, the ribs uniform, finely 
scabrous, the furrows 12, very fine and inconspicuous, rather shallow; sheaths 
& 
j 
’ 
3 
f 
loose, the lowermost somewhat inflated, 6-10 mm, long, those of the stem 
with 8-14 acute subappressed teeth, those of the ultimate branchlets acerose, 
2mm, long, spreading; strobilus borne on tips of leafy spring shoots before 
the sterile summer herbaceous ones, 
Known with us onlv from Priest R, drainage at 2500-3000 feet, Epling 6582, 
represent{-ar. pauciramosum Milde, with fewer ©) 
scattered whorls of branches than the typical species. 
——n moist woods. 
