100 
IOWA ACADEMY OP SCIENCE 
With respect to the water plants the distribution of the dominant forms is 
reversed, the seaward face having by far the richer flora. On this side toward 
the Strait, the water deepens rapidly, being fully thirty feet in depth at a dis- 
tance of seventy-flve feet from the water’s edge, as witnessed by the narrowness 
of the kelp zone. The daily tidal fluctuation here is about ten feet, and the 
shores on this side are strongly lashed by the waves of the open Sound. The 
algae growing here were not only unusually vigorous, but quite free, as well, 
from, diatoms and other attached forms. 
Most conspicuous of the marine algae here, as elsewhere on these coasts, is 
Nereocystis luetkeana, and R. These plants grow with vigor unusual for the 
region upon the submerged shores of Iowa Rock. Local flshermen report plants 
over eighty feet in length from this point, and no doubt larger ones are developed 
there, as the strong waves and tidal currents would favor their elongation. 
The adjacent shares of Loopez island, distant only a few rods, bore splendid 
specimens of Egregia menziesii, Aersch., but none of these was found on Iowa 
Rock, the shores being probably too precipitous for them. 
While the subtidal brown algae, including Nereocystis, Alaria, Desmarestia, 
etc., were numerous and well developed, there was a poverty of inter-tidal 
representatives of this group. Only a few dwarfed specimens of Pucus and 
Colpomenia were found. These seem unable to maintain themselves on the 
rocks in the face of such wave action as is here encountered. On the other 
hand, the inter-tidal red algae were conspicuous. The dashing of the spray 
doubtless facilitated the growth of such forms as Corallina, Amphiroa, Melo- 
besia, Prionitis, etc. The sub-tidal reds were also well represented by Nito- 
phyllum, Odonthalia, Cefatothamnion, S'arcophyllis, etc. 
It should be borne in mind that the list of algae from Iowa Rock given 
below includes only the relatively large and more conspicuous plants, and those 
growing there at one time (July 14, 1908). A detailed study, especially of the 
smaller forms, would add many names to the list, and observations continued 
through the succeeding seasons of the year, would likewise greatly extend it. 
My thanks are due Dr. T. C. Frye, Professor of Botany, State University of 
Washington, for assistance in determinations. 
Plants Noted Growing on Iowa Rock July 14, 1908. 
Algae. 
Chlorophyceas — • 
Ulva lactuca Wulf 
Cladophora sp. 
Codium mucronatum f. californicum 
J. Agardh. 
Phseophyceae — 
Laminaria bullata Kjell. 
Hedophyllum sessile Setch. 
Costaria turner! Grev. 
Alaria valida Kjell. & Setch. 
Nereocystis luetkeana P. & R. 
Desmarestia aculeata Lam. 
Desmarestia ligulata f. herbacea J. 
Agardh. 
Colpomenia sinuosa D. & S. 
Pucus evanescens Agardh. 
Rhodophyceae — 
Porphyra perforata J. Agardh. 
Iridaea laminarioides Bory. 
Nitophyllum ruprechtianum J.‘ 
Agardh. 
Odonthalia dentata Lyngb. 
Polysiphonia sp. 
Microcladia borealis Ruprecht. 
Prionitis lyallii Harvey 
Sarcophyllis californica J. Agardh. 
Corallina officinalis L. 
Amphiroa tuberculosa Endl. 
Melobesia marginata S. & P. 
Ceratothamnion pikeanum var lax- 
urn S. & G. 
Gloiopeltis furcata J. Agardh. 
