Jennings : A Botanical Survey of Presque Isle. 393 



Fades. — 



Sagittaria latifolia, Alisma plantago-aquatica. 



Secondary Species. — 



Cardatnine pennsylvanica, Radicula pahistris hispida, 

 Salix sp. (seedlings), Naiimbergia thyrsiflora, 



Isnarda pa/iisfn's, Stac/iys palustris, 



Dulichium aruudinacejim, Cicuta bitlbifera, 

 Carex comosa, Persicaria laurina, 



Persicaria incarnata, Rumex altissimus. 



This formation extends from slightly above water on the shore to 

 a depth of five or six inches, it being on rare occasions entirely out of 

 the water, due to a falling of the water-level in the bay, and often be- 

 ing inundated in times of higher water. 



The Salix discolor-liicida Formation. 



The Salix discolor-lucida formation is at its best at about the middle 

 of the driftwood habitat opposite the widest part of Horse-shoe Pond. 

 In places the shore becomes more xerophytic and the drift-beach, 

 thickly strewn with debris, supports Xanthiiwt and Argentina, but no 

 Cakile. Towards the entrance to Niagara Pond there is a narrow 

 zone of the Cladiiwi-Calaviagrostis formation backed by an Alnus 

 thicket with Corniis stolonifera and Cormis amomum at its outer edge, 

 but this thicket is being killed out by the shading effects of the Priinus- 

 Acer formation just behind it. 



The typical Salix discolor-lucida formation as exhibited along the 

 driftwood habitat of Presque Isle is as follows : 



Fades. — 



Salix discolor, Salix lucida. 



Secondary Species. — 



Salix cordata, Radicula pahistris hispida, 



Persicaria laurina, Cardamine pennsylvanica, 



Argentina anserina, Carex comosa, 



Xatithiuni cotnmutie, Erigeron ramosus. 



This formation differs here but little from its corresponding station 

 near the Head, excepting in the greater prominence of Salix lucida. 

 The latter species is here more prominent than is Salix cordata and is 

 extending itself out into the Sagittaria-Alisma formation in little 

 islands and peninsulas, where the driftwood and sand have risen above 



