80 
IOWA ACADEMY OP SCIENCES. 
lake, growing on gravelly bottom along the west shore, 
approaches the type in the character of the leaves. 
Potamogeton zosteroefolius Schum. Common in Clear lake, in 
flower. Also common in Lake Edwards. Common in the 
Okoboji lakes, some finely fruited, but most of them in flower. 
Not common in Rock river at Rock Rapids. 
Potamogeton foUosus Raf. Abundant in Lime creek near 
Forest City, mostly in flower. Mr. Cratty found it a month 
later in fine fruit. 
Potamogeton major (Pries) Morong. Common in Clear lake, 
some in fruit, but most of it in flower. Very common in the 
Okoboji lakes at their juncture. In good fruit, but flowering 
specimens were common. 
Potamogeton pussillus L. Rare in Clear lake at west end. 
Some in fruit, others flowering. Not common in East Okoboji 
lake near its northern extremity. The glands at the base of 
the leaf are well shown in most of the specimens. 
Potamogeton pectinatus L. Common, mostly in flower, in 
Clear lake. The specimens growing on sandy bottom at the 
east end of the lake were slender and few-leaved. Also com- 
mon in Lake Edwards. Very fine and in excellent fruit in East 
Lake Okoboji. Rare in Rock river near Rock Rapids. 
JSfais Jlexilis (Willd) R. & S. Very common in rather shallow 
water in Lake Edwards, Clear lake and Spirit. Growing on 
sandy or mnd bottoms. 
Zannichellia palustris L. Quite common and in fruit in shal- 
low water on gravelly bottom along the west shore of Spirit 
lake. Much finer specimens were found in East Okoboji lake 
in somewhat deeper water. The leaves were in excellent con- 
dition for collecting, and many species of aquatic plants which 
seldom fruit were found in splendid condition. The following 
algae, identified by Miss Lucy M. Cavanaghwere also collected : 
Chcetophora pisiformis (Roth) Ag. Common in West Lake 
Okoboji. 
GhcetopJiora monolifera Kg. Common on Gladophora in Clear 
lake. New to the state. 
Gladophora oMgoclona Kg. Common in Clear lake. 
Gladophora glomerata Kg. var. Common in West Lake 
Okoboji. 
Gladophora fracta Kg. Common in West Lake Okoboji. 
