No. 50.]} 181 
Orontivum, L. Golden Club, Floating Arum. 
aquaticum, L. In shallow water. May. 
Acorus, L. Calamus, Sweet Flag. 
calamus, L. Wet meadows and swamps. May-June. 
Orpver TYPHACEA. Tus Cart-rart Trise. 
Tyrua, L. Cat-tail, Reed Mace. 
latifolia, L. Borders of swamps and rivers. June-July. 
angustifolia, L. With the preceding. 
Sparcanium, L. Burr Reed. 
ramosum, L. In shallow ponds and streams. June. 
simplex, Smith. S. americanum, Nuit. Borders of streams. July. 
Orper FLUVIALES. 
Nasas, L. 
canadensis, Michz. Ponds and slow-flowing water. July. 
ZosTERA, L. Grasswrack. 
marina, L. Seashore and salt-water bays. 
ZANNICHELLIA, LL. Triple-headed Pondweed. 
i L.  Z. intermedia, Torr. Ditches and shallow ponds ; 
most common in brackish water. July. 
Ruppia, L. ) 
maritima, Z. Salt-water ditches. July. 
Potramoceton, L. Pondweed. 
natans, L. Ponds and slow-flowing water. July. 
heterophyllus, Schreb.? P. fluitans of American botanists. Ponds, 
| &ce. 
diversifolius, Bart. Flowing water. July-August. 
perfoliatus, L. Flowing water. July. 
prelongus, Wulff. P. luceus of American botanists. Slow-flowing 
deep water. July-August. 
compressus, L. P. zosterefolius, Schum.? Flowing water. July. 
gramineus, Michz. P. pauciflorus, Pursh. Small streams. July— 
August. 
pectinatus, Z. P. marinus, Miche. Fresh and brackish water. 
July. 
