Page:Popular Science Monthly Volume 60.djvu/211

Rh Not only did they prove of unusual taxonomic interest—some entirely new species being collected—but also well worthy of careful ecological research. Their zonal distribution, formation groups and choice of special substrata were noted, together with their behavior at different stages of the tide. Often very sharp lines of demarcation between different algal societies were exhibited. In Figure 8 an excellent example is reproduced. At the rear, near the center, is seen the characteristic fringe of salal (Gaultheria shallon) in front of which Enteromorpha colonies are established upon the flat sandstone. In the foreground appears a sharp zone of wrack (Fucus evanescens). In this view there is also shown some of the unusually vigorous epiphytic moss-vegetation so



abundantly represented on Vancouver island. Another very distinct instance of zonal distribution is shown in Figure 9, the photograph having been taken at low tide. In the foreground the slender leaves of a marine angiosperm (Phyllospadix scouleri) are seen, spread over which are fronds of Egregia, one of the most notable of the west coast kelps. The sides of the dome-shaped rock are draped with kelp, principally Egregia and Alaria, while the top is covered with a fairly uniform and copious growth of the alga which has passed under the name of Halosaccion hydrophora, but concerning which it is possible that an error has been made by American phycologists.

Under other topographic conditions the zonal distribution is not so