1912] Sinnott,— Pond Flora of Cape Cod 3l 
S. teres, probably rather common but found by the writer only in 
Sandwich, Barnstable, Yarmouth and Wellfleet. In shallow water 
and where the bottom is sandy it has short and stout phyllodes, but 
more commonly they are long and tapering. 
Eleocharis acicularis, on peaty shores everywhere. 
E. Robbinsii, the dominant plant in very shallow, peaty ponds, 
gradually encroaching from the shore and finally converting the whole 
pond into a grassy swamp. 
Cladium mariscoides, common on many ponds but often absent. 
Dulichium arundinaceum, abundant and delighting in the thick 
vegetation along the peaty shores. 
Rynchospora alba, locally common on peat. 
Eriocaulon septangulare, on muddy bottoms in shallow water 
everywhere. 
Xyris Smalliana, a striking species, usually confined to floating 
masses of peat, and fairly common where they are present. The 
writer has observed it in Barnstable, Harwich and Wellfleet. 
Juncus pelocarpus, common everywhere, but exceedingly abundant 
on certain ponds where there is a rather pebbly bottom and not 
much mud. It also thrives well above the water-mark. 
J. canadensis, often abundant at the water's edge. 
J. marginatus, rather common. 
Proserpinaca pectinata, locally common on mud. 
P. palustris, rare, found only an Snake pond in Sandwich. 
Myriophyllum tenellum, fairly common. 
Utricularia vulgaris var. americana, occasional. 
U. purpurea, common on muddy bottoms. 
U. biflora, rare, on sandier shores. 
Castalia and Pontederia are often present, and in the last stages of 
filling, when the pond has become a bog, other plants appear, which 
are more characteristic of the half-drained and muddy swamps. These 
are Sparganium americanum var. androclodum, Sagittaria latifolia, 
Cyperus dentatus, Eriophorum virginicum, Nymphaea advena, Bras- 
enia Schreberi, Sium cicutaefolium and many others. 
It will therefore be apparent that, as might be expected, a large 
percentage of the flora of the undrained sandy and peaty ponds, where 
conditions are very similar to those on Long Island and New Jersey, 
is composed ,of plants whose distribution is confined to the Atlantic 
coastal plain and its extensions. 
