98 Rhodora [JUNE 
* Hemicarpha subsquarrosa, Nees. Shore of Waushacum Pond, in 
sand ; and shore of Gleason's Pond, in gravel. In the latter situation 
it is matted with, and almost hidden by, plants of Fimbristylis autum- 
nalis, Roem & Schutt. 
* Eleocharis palustris glaucescens, Gray. Abundant on the shore of 
Waushacum Pond. 
Cladium mariscoides, Torr. Very abundant Qn margin of 
Waushacum, with Carex filiformis, Carex riparia and ZLleocharts 
palustris, forming a belt for long distances, from ten to twenty feet 
broad. The Cladium is by far the most conspicuous element. 
* Panicum xanthophysum, Gray. Not uncommon. 
* Panicum macrocarpon, LeConte. After consulting the specimens 
in the Gray Herbarium and comparing with the descriptions in 
Britton & Brown’s Illustrated Flora, I am convinced that most of what 
passes for P. latifolium from New England is properly referred to ?. 
macrocarpon. Certainly my specimens belong there. 
* Panicum sphaerocarpon, Ell. Abundant. 
* Panicum Atlanticum, Nash. Not common. 
* Panicum boreale, Nash. Not common. 
* Panicum Columbianum, Scribn. Common. 
* Panicum pubescens, Lam. Common. 
Not all these Panicums are actual additions to the list, though the 
names are new there, being the result of recent special work on the 
perplexing dichotomum group. 
* Bromus brizaeformis, Fisch. & Meyer. Collected for three years 
past on a dump near Leonard’s Pond. 
FRAMINGHAM, Mass. 
THE POLLUTION OF WATER-SUPPLIES BY ALGAE. 
G. T. Moore. 
Tue question of a pure water supply is one which is of so much 
importance and interest that it can hardly be said to apply to any 
special locality. Throughout the country more and more attention is 
being given to it by both engineers and biologists, and new problems 
are constantly developing with regard to it. To Massachusetts, how- 
ever, is due the credit of being the first state to begin any systematic 
