62 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
from the water side, a gradual but striking change in the character of the leaves is 
evident. In the deeper water the petioles are rigid, sharply triangular, and tipped 
with a narrow blade sometimes scarcely distinguishable from the petiole. Nearer the 
land the blades are broader and the petioles shorter, and in the mud along the shore 
plants grow with broadly lance-shaped blades on petioles 8 to 10 inches long (pi. 15, 
fig. 1). Not infrequently blades are found with one or both sides lobed. This species 
also occurs on the other shore with Sciipus lacustris, but is not as abundant as on the 
east side. Wherever Sagittaria rigida and Scirpus lacustris occur together the former 
always occupies the deeper water. Near the shore Typha latifolia , Carex pseudo- 
cyperus var. comosa , and species of Scirpus form a background for the Sagittaria. 
Scirpus lacustris is scattered along the cast shore, but is not as abundant as on 
the other side, a few hundred feet away, where Scirpus pungens is the prevailing 
species. There are relatively few macroscopic forms in the water among the plants 
of Sagittaria and Scirpus , although various species of algae are attached to the 
Sagittaria petioles. Ceratoph yllum occurs, but not as abundantly as in the water 
between the two shore regions. Along the south shore there is a thick growth of 
Dianthera americana , and the shallow water of the harbor is tilled with submersed 
forms, of which Vallisneria spiralis, MyriophyUum spicatum, Nairn jlexilis , Cerato- 
phyllum demersum, and the various species of Potamogeton are the principal ones. 
These all grow together freely, the Naias in company with Ohara, mostly Ohara 
fragilis , covering the bottom as clover covers a field, while the other species nearly 
all rise to the surface. In the early part of the season few or no plants can be seen, 
but after the middle of August the surface of the water is covered with their floating 
branches. A patch of Nuphar advenct and one of Nelumbium luteum , the latter but 
recently established, occupy part of the head of the harbor. Characece are scarce in 
this harbor, excepting some Ohara fragilis in the deeper parts and a few smaller 
species on the edges of a little clay bank near the south end. Here were found, in 
water from 2 to 10 inches deep, a number of species, some in vigorous condition, 
other’s barely holding their own. Here I also found Zannichellia palustris. 
The growth of Sagittaria rigida along the east side of Squaw Harbor is doubtless 
due to the protection from wave action afforded by Gibraltar Island and Bar in the 
mouth of the main harbor. The west side is more exposed to waves than the east 
side, and while Sagittaria is not a plant that endures heavy wave action, Scirpus 
pungens grows equally well on a muddy fiat or on a surf-beaten bar. In this place 
it runs out along the point toward Gibraltar Island as far as it can find footing 
among the rocks where the water is not too deep. The thick growth of filamentous 
algie on the petioles of Sagittaria 'rigida and over the stones along the east shore 
must also be attributed, at least partly, to protection from wave action. (Edogonium 
and Spirogyra grow luxuriantly attached to Sagittaria petioles just beneath the 
surface of the water, and these masses swarm with minute forms of animal and plant 
life. Pithophora sp. covers the stems and petioles in shallow water as well as the 
mud and damp stones along the shore. The coarse filaments of this alga form a 
network whose meshes are filled with Crustacea, insect larvae, and unicellular algae. 
Plants near Gibraltar Island. — The same species that flourish in Squaw Harbor 
extend out into the main bay to a depth of 10 feet or a little more. Everywhere 
from Gibraltar Island to the shore of South Bass Island the bottom of the bay is 
covered, generally thickly, with plants of which Naias jlexilis and var. robusta , 
