544 



BULLETIN OF THE) BUREAU OP 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 parts 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 (n), present on the 

 upper portions of every rock above low- water mark (the dotted lines). Near low- water mark was a brown 

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

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

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

 abundant September 19 (chart 273), had almost disappeared, and there wasno Polysiphonia violacea, gen- 

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



List of algae: Calothrix scopulorum, 1, patches on the top of Pyramid Rock; Ulva Lactuca var. rigida, 

 5, bases of old plants; Enteromorpha intestinalis , 7, few scattered plants; Cladophora lanosa var. uncialis, 

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

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

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

 water; Myrionema corunnm, 30, on Laminaria; Laminaria Agardhii, 33, many old plants; Fttcus vesicu- 

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

 scattered plants; Acroch<Etium secundatum, 38, on Porphyra; Acroch.cctium virgatulum, 39, on Ceramium; 

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

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



o 



