Columbian Region. 593 
In this great coniferous forest, the trunks of trees two or three hundred feet 
in height are often only separated, according to my observations, by the space 
of a few feet. The ground shaded throughout the year by the impenetrable 
canopy of forest, never becomes dry; it is densely covered by a thick carpet 
of mosses, ferns (see Fig. 6, p. 265) and other plants. The more open por- 
tions are choked by an impenetrable growth of undershrubs. The soil which 
has produced the maximum growth of forest in this region is, outside the 
river bottoms, a thin porous gravel of glacial origin, rarely more than a few 
inches deep. The luxuriance of tree growth, therefore, illustrates the influ- 
ence of a heavy rainfall and temperate climate upon the forest. 
: A. Puget Sound—Cascade District. 
This district comprises all of the flat sound country dominated by characte- 
ristic groups of plants, including the mountainous country, of the Cascade 
Mountains. ; 
1. Before describing the forests a few remarks are necessary upon the Beach-, Salt 
Marsh- and the Marine Algal-Formation. — This coast is characterized by forms like 
Dietyoneuron, Postelsia, Laminaria Sinelairii, L. Andersonii and Fucus Harveyanus. The tide- 
pool vegetation of Port Renfrew, Vancouver Island, is distributed as follows: 
High-tide pools. Corallina aculeata, Codium mueronatum, Phyllospadix Seouleri, 
Amphiroa cretacea,' Cheilosporum planiusculum. Phyllospadix Scouleri [see Fig. IT er p- 314) 
oceurs in great abundance over the jagged sandstone rocks exposed only at low tide and in most 
of the numerous tide pools along the shore.- Mixed with species of algae it forms a shelf waich 
varies in width with the slant of the shore and the depth of the water, as it grows nowhere in 
very deep water. Zostera marina is found in the sheltered coves of the inner San Zu Harbor 
of Puget Sound and in these places it grows from a muddy, or sandy bottom, while epiphytic upon 
it is Porphyra naiadum. 
Mid-tide pools. Species of Amphiroa, 
frondescens, Rhodomela larix, Soranthera ulvoides, 
borealis, Endocladia muricata, Halosaccion hydrophora. 
Low-tide pools. Laminaria and Alaria sp., Iridaea eh ; : EEE 
vancouveriensis. Nereocystis Luetkeana with its long stem readily er itself to the dept nö 
the water. Clinging to this are Ulva lactuca, Enteromorpha intestinalis, The Ange 
Surge and surf plants such as Lessoniopsis, Laminaria, Hedophyllum and Costaria oceur only ın 
limited numbers i ide pools®. 
Sand Besch je et Along the front border of the large ‚sorge beaches as on or‘ 
southwest shore of Vancouver Island, Occur Juncus Lescuri, DERUREN. major, Potentilla ee 
var. grandis, Trifolium heterodon. Farther back on the middle or arift wood beach Be en 
mollis, Festuca Jonesii, Bromus and many herbs. The upper beach in var gr m, 
fized by Aira caryophyllea, Deschampsia caespitosa, Carex macrocephala - ee 
Upon the small sand beaches at the mouths of ravines, it is difficult to differentiate 
lower and the upper beaches. No one species preponderates. 
The Salt eh Formation is se on low shores Beme the mouths of, wor en, 
they are occasionally covered by high tides. The most characteristic plants 2 DOCBER BR 
Salicornia ambigua, Arenaria peploides, Atriplex littoralis, Carex eryptocarpa etc. 
Codium, Corallina, Cheilosporum californicum and 
Laminaria Cloustoni and bullata, Microcladia 
Lessoniopsis littoralis, Corallina 
a i t 
R, S. A.: Observations on the tide pool Vegetation of Port Renfrew, Minnesota 
I) SKINNE 
Botanical Studies, 3. ser. Part II, 1903: 145. 
Harshberger, Survey N.-America. 
38 
