Isoetes saccharata, 
Plants growing in colonies; leaves linear, olive-green 
in color, 5-13.cm. long, 10--20in a cluster; sporangia 
oblong, 5 mm. or less in length. 
Along riverbanks between tidal limits. 
In various localities along Chesapeake Bay from Wi- 
comico River northward : along Potomac River, Eastern 
Branch, Fourmile Run, Stee/e; Hunting Creek, Vasey, 
Coville ; Notley Hall, Mt. Vernon, Covélle. 
The geographical distribution of this species and its 
forms has been discussed at length by G. A. Shull [ Bot. 
Gaz. 36: 187. 1903. |. 
tt Leaves 20 cm. or longer. 
2.1. valida (Engelm.) Clute. 
Lsoetes Eengelmanni valida E’ngelm. in Gray, Man. 
O77 ed. 0. 700, \Onderw.dutlil, ble 1.7 48; Nat. 
Ferns 147; in Britt. Man. 209. 
I. valida Clute, Fern Allies 236. 
Plants sometimes 4 cm. thick at the base; leaves 50 to 
200 in number, sometimes 6 dm. long; sporangia ob- 
long, 1-2 cm. long. 
in pooisiand ditches. Summer. 
Near Great Falls, Potomac River, Ward; Salt Pond 
Mt., Va., Candy. 
26. EQUISETUM Plinius. 
Liquisetum, hippuris Grects dida etin pratis vi- 
tuperata nobis —est autem pilusterre equine sacte 
similis. Plinius, Hist. Nat. xxvi, 132. 
54 
