384 TRANS. ST. LOUIS ACAD. SCIENCE. 



and dark gray when dry; in some I find the warts much smaller than in 

 others, but never wanting; microspores also quite dark brown. 



* * With peripheral bast-bundles. 



f Velum partial. 



9, I. Engelmaxni, a. Braun. Our largest species with numerous (25 

 to 100) long (9 to 20 inches or more) light green leaves with abundant 

 stomata; sporangium usually oblong to linear-oblong, unspotted; velum 

 narrow; ligula elongated from a triangular base; macrospores 0.40 to 0.52 

 mm. thick, deli'cately honeycomb-reticulated ; microspores 0.024 to 0.028 

 mm. long, generally smooth. — Flora 1. c. ; Am. Jour, 1. c, ; Gray Man, 1, c. 



Var. GRACILIS, Engelm. Often submerged, with fewer (8 to 13) leaves, 

 9 to 12 inches long; the bast-bundles sometimes quite small, or only two 

 of them. — Gray Man. 1. c. 



Van VALiDA, Engelm. The stoutest of all our species; leaves 50 to 

 100 or even 200, i8 to 25 inches long, keeled on the upper side; sporan. 

 gium often linear-oblong (4 to 9 lines long), J or often J or even | covered 

 by the broad velum ; macrospores rather smaller, 0.32 to 0.4S mm, thick; 

 microspores 0.024 to 0.027 mm. Ipng, spinulose,— Gray Man. L c. 



Var. Georuiana. Similar to the type ; leaves few (in the only speci- 

 mens seen 15, 10 to 12 inches long), rather slender ; oval sporangium with 

 narrow velum; macrospores larger, 0.48 to 0.56 mm. thick; microspores 

 0.028 to 0.031 mm. long, smooth. 



In ponds and ditches, immersed in mud, rarely found in slow-running 

 streams, in company with the ordinary vegetation of such localities, 

 Bidens-, PoIygonu?n, Lycopus^ Caricts^ Leersta^ etc.; mature in summer; 

 probably throughout the middle States, but thus far only found — from 

 Massachusetts: Arlington brook, Alewife brook, West Cambridge brook, 

 Woburn, Wm. Boott. Rhode Island: Newport, W, G. Farlotv, Connec- 

 ticut: Meriden, i?*. TV, Hall— to New York r Peekskill, W. H. Leggett. 

 New Jersey : R. Durand^ C. F. Austin^ and others. Pennsylvania, Beth- 

 lehem, C. J, Moser, E. Durand, S. WoUe; Delaware Water-Gap, 5. W. 

 Knipe; Darby, y, G. Hunt; Philadelphia, E. Dnrand, C. B, Smith, and 

 others. Delaware: Wm, M* Canby, A> Commons, Virginia: Salt Pond 

 yiovLntZi.myWith. Parnassia asati/oliuj W.M. Caudy, Missouri: St. Louis, 

 iV, Riehl and G^Engehnanyi^ 1S42, in a single locality, where it was soon 

 afterwards destroyed by cultivation : :not found otherwise west of the Alle- 

 ghany Mountains- Var. gracilis seems to be a northern form : Brattle- 

 borough, in Clark's Pond, C C. Frost ; Colebrook's, in a shallow stream 

 with gravelly bottom, y. W. Rohbins '^ New Haven, in fresh water on a 

 tidal shore, D. C. Eaton; Newport, Bridges, G. Thurber; Passaic river, 

 near low- water mark, y, Ennis. Var, valida was discovered in Pennsyl- 

 vania near Warrior's Mark, Huntington Co., and Smithville, Lancaster 

 Co,, T. C. Porter; and in Delaware, Wilmington, JV, M. Canby. Van 

 Georgtana comes from a mountain stream, Georgia, the Horseleg creek, 



