6-7 EDWARD VII. 



SESSIONAL PAPER No. 22a 



A. 1907 



VII 



THE SEAWEEDS OE OANSO. 



Being a Contribution to the Study of Eastern Nova Scotia Alg^e' 

 BY C. B. EOBINSON, B.A., PICTOU ACADEMY. 



The month of August spent by me at the Marine Biological Station during its 

 second season at Canso (1902) was almost entirely devoted to the determination of the 

 Marine Algse. 



The region was such as to permit the gathering of species having the most varied 

 habitat, deep-water forms being occasionally dredged in great abundance, while Ldm- 

 inarice and Fuci, with their associates, grew nearly everywhere below and between tide 

 marks. Tide pools of varying range and size were also easily accessible, and the quieter 

 coves and the wharves yielded other forms. My available time, indeed, proved quite too 

 short for a complete investigation of this portion of the flora of the district. 



The clear water frequently made it possible to see large patches of algae growing 

 upon the bottom at depths of about ten fathoms. The results obtained by dredging in 

 these and somewhat deeper places indicated that the bulk of this was composed of 

 Ptilota pectinaia, acting as host, however, to many hydroids and other small animals, 

 besides several species of red algae. Of the latter, Delesseria alata was much the most 

 frequent, though the plant seen thus in greatest quantity upon any single occasion was 

 Euthora cristata angustaia. Bhodophyllis dichotoma was also obtained several times, 

 and four species of Oallithamnion occurred, of which G. Pylaisoei and C. Americanum 

 were the most plentiful. A small form -^f this genus, also one each of Ceramium and 

 Polysiphonia, were often found upon the larger algse and upon hydroids. These were 

 always sterile, and could not be identified. On the stouter portions of Polysiphonia 

 two microscopic encrusting species also grew, one Erythrotrichia ceramicola, the other 

 may be the European Actinococcus. 



Odonthalia dentata and Bhodomela subfusca were each dredged on a single occa- 

 sion only. 



In deep places under wharves beautiful specimens of Delesseria sinuosa could 

 be gathered, and it also was frequently found in the dredge. The corallines were also 

 abundant, and six species of Polysiphonia were collected, of which P. urceolata, often 

 fruiting, was the most plentiful. The determination of P. Olneyi rests upon a few 

 sterile filaments, and may be inaccurate. 



But perhaps the most striking fact regarding the red algse was the comparative 

 scarcity of some of the best known and most widely distributed genera. Ceramium 

 was represented by a few filaments; Ohondrus and Rhodymenia were seen out rarely, 

 Gigartina only once. 



The PhceopJiycece constitute much the greater part of the littoral flora, and while 

 not quite equalling the Florideoe in the total number of species found, far surpass them 

 in individuals. 



Among the Fuci were F. evanescens and F. filiformis, the former washed ashore 

 near the laboratory, the latter gathered in tide pools on Cranberry. F, serratus, which 

 rivals F. vesiculosus in abundance at Pictou, and which has recently been found on the 

 Cape Breton coast, was carefully watched for, and apparently does not occur. 



Chorda iilum, everywhere plentiful, grew in great luxuriance in Grassy Cove, the 

 fronds usually exceeding twenty feet in length. Agarum Turneri was found in several 



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22a— T* 



