BIOLOGICAL SURVEY OF WOODS HOLE AND VICINITY. 



539 



Chart 269. — Distribution of alg^e on Spindle Rocks, May 22, 1905. 



The rocks at this date presented a characteristic algal flora of the spring at its full development. 

 There was notjnuch change in the species since April 22 (chart 268), but a large increase in the quantity 

 of vegetation. Cladophora lanosa var. uncialis (11 ) was still the dominant green alga, but Enteromorpha 

 intestinalis (7) had begun to appear; these two species extended the green zone much higher up on the 

 rocks than where it was a month previous (chart 268). The brown zone at low-water mark (the dotted 

 line) and just below, composed chiefly of Eciocarpus penicillatus (18), Phylliiis fascia (24), Scyiosiphon 

 lomentarius (26), and Chordaria /lagelliformis (28), was also broader and more evident. Polysiphonia 

 urceolata (47) formed a conspicuous red zone below the brown, with extensive growths of Chondrus 

 crispus (49) extending into deeper water. 



List of species: Enteromorpha intestinalis, 7, young plants; Cladophora lanosa var. uncialis, ir, 

 abundant; Ectocarpus fasciculalus , 15, abundant on larger algx; Ectocarpus penicillatus, 18, abundanton 

 larger algjc; Sorocarpus uvoeformis , 21, few on mussel shells; Desmotrichum baliicum, 22, few mixed with 

 Scyiosiphon; Desmotrichum undulatum, 23, few mixed with Scyiosiphon; Phyllitis fascia, 24, very abun- 

 dant; Punclaria plantaginea, 25, few; Scyiosiphon lomentarius, 26, abundant; Desmarestia viridis, 27, 

 very abundant; Chordaria flagclliformis . 28, much; Chorda tomentosa, 32, abundant; Laminaria Agardhii, 

 33; Ceramium rubrum, 43, abundant; Polysiphonia urceolata, 47, abundant; Polysiphonia viotacca, 48, 

 few; Chondrus crispus, 49, abundant. 



