290 FLORA OF PLYMOUTH SOUND 



Dredging Results. 



I was early anxious to ascertain whether the southern and sub- 

 tropical weeds which reach their northern limit on the south coast 

 of England (in many instances), and which are mentioned by 

 Boswarva and others as found occasionally washed ashore on the 

 east (Bovisand) and west (Mount Edgcunibe) sides of the Sound, 

 had definite localities in the Sound ; and whether, if such localities 

 occurred, they were such as to account for the occasional presence 

 on the two shores of the same rare species. With these objects in 

 view I dredged along the two shores and across the Sound, outside 

 and within the Breakwater. Outside the Breakwater the huge rocks 

 interfered with my plans ; inside, the cables connecting the main forts 

 caused much trouble. Spite of these drawbacks the results were 

 such as to show that the weeds referred to (e. g. Stejiogramme 

 interrilpta, Spy^'idia filamentosa, Scinaia furcellata, Dudresnaia 

 coccinea, Halymenia ligulata, Spondylothamnion multifida* Anti- 

 thamnion plumula, Sporochnus pedunculatus, Arthrocladia villosa, 

 Taonia atoinaria) have a habitat in the Sound, and are, in nearly 

 every case, found in some spots in quantities large enough to allow 

 one to assign to them definite localities, from which (as I proved) 

 further supplies could be drawn. The dredge, used along the 

 eastern part of the Sound from Bovisand Pier to Batten Pier, 

 yielded only poor results. With the exception of one or two 

 patches in Jenny cliffe Bay, Rum Bay, and Batten Bay, the sea 

 bottom was muddy and comparatively free from weeds. I need not do 

 more than refer to the effect I have supposed the Breakwater to have 

 had on the eastern part of the Sound. No doubt the winds which 

 in the stormy times before 1841 washed dead bodies into Rum Bay 

 would, in calmer weather, bring enriching algal spores. One of the 

 richest localities in the Sound is that included in the triangular area 

 formed by joining Bovisand Pier, the Beacon on the east end of the 

 Breakwater, and the Duke Rock Buoy. The region round the Duke 

 Rock Buoy is especially good ; that south of the buoy may be taken 

 as a habitatt for Stenogramme interrupta, Dudresnaia coccinea, Scinaia 

 furcellata, Halymenia ligulata, Antithamnion plumula, Spondylo- 

 thamnion muUifida, and Taonia atomaria. I found Stenogramme 



* I use throughout these pages the specific names employed by Hauck in Die Meeres- 

 algen, 1885 (llabenhorst's Cryptogamen-Flora, ii). 



t It should be remembered that my personal knowledge was gained in the months of 

 Avigust and September, and that my remarks refer of necessity to these two months. I do 

 not attempt any comparison between the flora of Plymouth, Torquay, Falmouth, and such 

 places. 



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