1902] VEGETATION AT WOODS HOLE 443 
formation of the floating vegetation. When a pond happens to 
be of nearly uniform depth, of 1™ or less, Nymphaea may grow 
ina luxuriance almost incredible. In such a pool, perhaps 150 
meters in diameter, near Succonesset point, water lilies were 
growing and blooming in such profusion that when it was found 
in July the surface of the pond seen through the trees gave the 
ay 
————— 
= z A 
Fic. 4.—South shore of Long pond. 
Limnanthemum and 
e 
fect of an unbroken sheet of white. ae 
Brasenia are in some cases important constituents of the fi 
Pond vegetation. 
Th Certain places Hypericum boreale take 
This Plant shows an interesting dimorphism. 
itged as a sparingly leafy unbranched axis, W 
o by its own buoyancy. When it reaches the ss ining 
“et, it breaks out into a strong branching — ee AaB 
MASSES of aerial foliage from enlarged stems sone iG it 
eon the surface. At Flax pond, in about 307 oF W: ae 
"Ms thus continuous floating masses many square — 
s floating 
5 a leading part. 
It grows sub- 
eak and slender, 
how- 
