MICHIGAN ACADEMY OF SCIENCE. 141 



Potamogeton amplifolius Tuckerm. Large-leaved Pondweed. — Frequent 

 in Sarnia Bay and in coves of streams. 



Potamogeton hererophyllus Schreb. Various-leaved Pondweed. — Fre- 

 quent along the borders of streams, especially about the mouths of St. Clair 

 River. 



Potamogeton angustifolius Berchtold and Presl. Ziz's Pondweed. — Fre- 

 quent about the mouths of St. Clair River. 



Potamogeton lucens L. Shining Pondweed. — Frequent in coves and still 

 water about the mouths of St. Clair River. 



Potamogeton praelongus Wulf . White-stemmed Pondweed. — Frequent in 

 still water near the mouths of St. Clair River. 



Potamogeton richardsonii (Benn.) Rydb. Richardson's Pondweed. — Fre- 

 quent in still water about the mouths of St. Clair River. 



Potamogeton perfoliatus L. Clasping-leaved Pondweed. — Common in St. 

 Clair River and its mouths. 



Potamogeton zosterfolius Schumacher, Eel-grass Pondweed. — Frequent 

 along the mouths of St. Clair River. 



Potomageton hillii Morong. Hill's Pondweed. — Frequent in still water 

 near the mouths of St. Clair River. 



Potamogeton obtusifolius Mertens & Koch. Blunt-leaved Pondweed. — 

 Frequent in and about the mouths of St. Clair River. 



Potamogeton friesii Rupr. Fries' Pondweed. — Frequent in still water near 

 the mouths of St. Clair River. 



Potamogeton pusillus L. Small Pondweed. — Frequent in coves and still 

 water along and near the mouths of St. Clair River. 



Potamogeton lateralis Morong. Opposite-leaved Pondweed. — Frequent 

 along and near the mouths of St. Clair River. 



Potamogeton vaseyi Robbins. Vasey's Pondweed. — Frequent in still and 

 slowly flowing water in big ditches and about the mouths of St. Clair River. 



Potamogeton rutilus Wolfgang. Slender Pondweed. — Frequent in still 

 and slowly flowing water along the mouths of St. Clair River. 



Potamogeton foliosus Raf . Leafy Pondweed. — Frequent in still water along 

 and near the mouths of St. Clair River. 



Potamogeton foliosus niagarensis (Tuckerm.) Morong. Smaller Leafy 

 Pondweed. Frequent in slowly running water along the mouths of St. Clair 

 River. 



Potamogeton hybridus Michx. Rafinesque's Pondweed. Frequent in 

 still and shallow water near the mouths of St. Clair River. 



Potamogeton dimorphus Raf. Spiral Pondweed. — Frequent in still water 

 and ditches along and near the mouths of St. Clair River. 



Potamogeton filiformis Pers. Filiform Pondweed. — Frequent in shallow 

 water along St. Clair River and its mouths. 



Potamogeton pectinatus L. Fennel-leaved Pondweed. — Abundant along 

 and about the mouths of St. Clair River. 



Potamogeton robbinsii Oakes. Robbin's Pondweed. — Frequent in still 

 water near the mouths of St. Clair River. 



Najas flexilis (Willd.) Rostk. and Schmidt. Slender Naias. — Frequent in 

 Sarnia Bay, in coves and ponds throughout. 



Najas flexilis robusta Morong. Larger Naias. — Frequent in still water. 



Jiincaginaceae. Arrow Grass Family. 



Scheuchzeria palustris L. Scheuchzeria. — In wet and marshy ground at 

 Port Franks. Apparently rare. 



