Inter-tidal Zonation — CARNAHAN 
39 
Fig. 3. Zonation on sea wall (steep, solid surface). 
From top: Saxostrea' glomerata, Vermilia carinifera, 
Codium adhaerens. 
Much variation is produced within the 
levels of the association by the dominance of 
subordinate species under special conditions. 
Codium adhaerens flourishes on steep slopes 
(Rg- 3) and in shade, while the seasonal 
Splachnidium rugosum dominates on some 
fairly exposed slopes and boulders. Cystophora 
torulosa and Xiphophora chondrophylla var. 
minus occur at the junction of the Corallina- 
Hormosira and brown kelp communities in 
fairly exposed localities, and exhibit domi- 
nance with moderate and strong exposure, 
respectively. Aeodes nitidissima assumes sea- 
sonal local dominance at similar levels in 
more sheltered areas. 
Sublittoral Brown Kelp Formation 
This formation is represented by a very 
consistent association, which forms the kelp 
belt that encircles the island. 
10. Carpophyllum-Ecklonia association 
(Fig. 2) ^ 
Ecklonia radiata var. richardiana d 
Carpophyllum maschalocarpum d 
C. flexuosum a 
C. plumosum a 
Pterocladia lucida f 
P. capillacea f 
Melanthalia abscissa f 
Sargassum sinclairii o 
Carpophyllum maschalocarpum, the principal 
Carpophyllum species, is generally present in 
larger proportions than Ecklonia. In addition, 
Carpophyllum flexuosum occurs with shelter and 
C plumosum with exposure. Sargassum sin- 
clarii is scattered within the association in 
sheltered places. Prominent subordinates in 
exposed areas are Pterocladia lucida, P. capil- 
lacea, and Melanthalia abscissa. 
11. Mytilus canaliculus-Tunicate fascia- 
tion 
This community occurs on vertical and 
shaded surfaces, which are unsuitable for the 
general establishment of the large phaeo- 
phyceans. Scattered specimens of Ecklonia and 
Tethya fissurata occur in the community. 
Fig. 4. Communities of Scoria Flat Inlet. Salicornia- 
Stipa associes (above), Avicennia officinalis consocies 
(showing pneumatophores), Saxostrea glomerata on 
vertical rock surfaces, and Hormosira banksii where 
there is sediment. 
SERAL COMMUNITIES (Fig. 4) 
The maximum development of serai com- 
munities takes place on sedimentary sub- 
strata in sheltered places. There is a zonation 
of several communities, each dominated by 
angiosperms. In each case, aggradation, 
characteristic of serai communities, occurs. 
1. Salicornia-Stipa associes 
Salicornia australis d 
Stipa teretifolia d 
Khizoclonium hookeri f 
