Marshall—The Vegetation of Twin Island. 
791 
Taraxacum taraxacum (L.) Rarst (?) 
Anaphalis margaritaceae (L.) Benth. & Hook. 
THE WATER ZONE. 
Except upon the west end where the marsh joins it, the island 
is surrounded by shallow water which supported a fringe of 
aquatic plants. The most common Was Scirpus fluviatili's 
(Torr.) Gray, which on the north side extended out five meters 
from the shore; 8. lacustris grew around the eastern point and 
north, hut was not as common as upon the borders of the other 
island. At this point, in fact, was the widest and densest 
fringe. Here was found the cat-tail ( Typha latifolia L.), com¬ 
mon on the marsh and on the border of Harper’s Island near 
by, but in flower in only one or two cases here. Hear an old 
landing were several plants of the yellow water-lily ( Nymphaea 
advena Soland.); this, too, is common at Harper’s Island 
whence it may have come. One very small plant was found 
on the south side; this probably came from the marsh west of 
it; none of these plants had flowered. Sagittaria latifolia 
Willd. invaded the water from the strand. On the north side 
among sedges grew the bur-reed ( Sparganium androcladum 
(Engelm.) Morong.), and on a pebbly beach two large clumps 
of willow ( Salix Unearifolia Rydb.) Lastly, there were two 
large patches of pickerel weed ( Pontederia cor data L.) on the 
south shore. Here and there near shore, especially on the south¬ 
west, there were dense growths of several small submerged 
plants, as Philotria canadensis (Michx.) Britton. In early 
July the water was fairly thick with the alga, Rivularia echin - 
ulata. 
PLANTS OF THE WATER. 
Philotria canadensis (Michx.) Britton 
Sagittaria latifolia Willd. 
Spirodela polyrhiza (L.) Schleid. 
Sparganium androcladum (Engelm.) Morong. 
Typha latifolia L. 
Pontederia cordata L. 
