544 



BULLETIN OF THE BUREAU OF FISHERIES. 



Pyramid Rock 



Chart 274. — Distribution of algae on Spindle Rocks, December 30, 1904. 



This chart plots the vegetation on the rocks in the winter before the upper ports are scraped clean by 

 floating ice. In the series of charts it shows the conditions two and one-half months before those pre- 

 sented on chart 267. The prevailing green alga was Cladophora lanosa var. uncialis (ii), present on the 

 upper portions of every rock above low- water mark (tlie dotted lines). Near low-water mark was a b^o^^-n 

 zone of Phyllitis fascia (24) and Scylosiphon lomentarius (26). Phyllitis fascia, which disappears in the 

 summer, had returned in abundance. Below low water was a red zone of Ceramium rubruni (43), very 

 plentiful, and in deeper water was the ever-present Chondrus crispus (49). Polysiphoniafibrillosa (46) , so 

 abundantSeptemberi9(chart273), had almost disappeared, and there was no Polysiphonia violacea, gen- 

 erally characteristic of the summer. Only a few plants of Nemalion mullifidum (40) remained. 



Listofalgse: Calothrix scopulorum, i, patches on the top of Pyramid Rock; U Iva Lactuca \3X . rigida . 

 5, basesof old plants; Enteromor pha intestiiialis, 7, few scattered plants; Cladophora lanosa var. uncialis, 

 II, abundant on the top of every rock; Ectocarpus granulosus, 16, abundant on Sargassum and other 

 large algse below low-water; Ectocarpus tomcntosus, 20, abundant on larger algae below low-water; 

 Phyllitis fascia, 24, abundant above low-water; Scytosiphon lomentarius, 26, very abundant above low- 

 water; Myrionema corunnce, 30, on Laminaria; Laminaria Agardhii, ^t,, many old plants; Fucus vesicu- 

 losus, 35, few scattered plants; Sargassum Filipendula, 36, few young plants; Porphyra laciniala, 37, 

 scattered plants; Acrochcetium secundatum, 38, on Porphyra; Acrochatium Tirgatulum, 39, on Ceramium; 

 Nemalion multifidum, 40, few plants; Ceramium rubrum, 43, very abundant; Polysiphonia fibrillosa, 

 46, few plants; Chondrus crispus, 49, abundant. 



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