(28) 



So patient is this species of drought that it may almost be considered 

 amphibious. It makes its first appearance at or even a httle above high 

 water, where it can only be reached by the waves at the highest tides- 

 Under such circumstances, in calm weather, the plants must often remain 

 dry for days together, and in such cases must be quite dried up ; yet 

 when again covered by the tide they will imbibe the moisture, and to all 

 appearance recover their vitality and growth. 



It is curious and very interesting to observe the remarkable sensibility 

 to light and air evinced by sea- weeds in their selection of a place of growth ; 

 some species, as Griffithsia setacea, are never found but in places which 

 are shaded from the noonday sun, others form a narrow fringe round the 

 margin of tide-pools, never reaching above six or eight inches from the 

 surface, while some others, as Phylhi^hora 7'ubens and membranifolia, 

 delight to grow under the shade of these, screened from the direct 

 rays of the sun, as well as from every eye except that of the enthusi- 

 astic collector. The present species, on the other hand, althovigh it 

 would rather die than live at a distance from the briny wave, yet is 

 equally intolerant of more than a good bathe once or twice a-day. 

 Hence, it never vegetates beyond a few inches under high-water, so 

 that it can only be exposed for an hour or two, or at most three, to 

 its influence at each tide. At high-water mark it may be observed 

 growing at the base of the rocks, while as it recedes from the shore its 

 zone ascends, or rather the rocks descend until they are below its level, 

 and the plant disappears. 



EXPLANATION OF PLATE CXL. 



Fig. 1. — Fucks canalicidcdus, natural size. 

 2. — Receptacles. 

 3. — Portion of same. 

 4. — Section of frond. 

 5. — Section of conceptacle. 

 6. — Spore. 

 7, 8. — Filaments from conceptacle. All magnified. 



