Marine Plants on the N. E, United States. 23 



found. Here almost all its species grow to their greatest per- 

 fection, both as to quality and quantity. A reason for this may 

 be that the bright green color which distinguishes most of the 

 species requires a larger amount of sun light for its production 

 than the olive, and red-colored plants require which inhabit lower 

 zones and deeper water. The color of those plants of the order 

 Ulvacece which travel into deep water, is for the most part of a 

 darker hue than tbose which grow in shallow places. I have 

 also noted that the color of specimens from the tropical and subtro- 

 pical regions is more brilliant and permanent than is that of plants 

 iu the colder regions of the north. Some of the species of this or- 

 der have besides a special love for fresh water, either in the shape 

 of land drainage or of shallow streams. Enteromorpha clathrata 

 for example may often be seen travelling far up fresh water 

 rivulets. 



In this zone Ulva lotissima is found in great abundance and 

 beauty. Wherever pools of water are left by the tide this plant 

 finds a happy home ; rejoicing in the heat and light of the sun it 

 spreads out its broad ruffled fronds, with a gentle undulating mo- 

 tion in the water. It is often gemmed with glistening glubules 

 of eliminated oxygen, thus purifying the wa^ er and contributing 

 both to the health and shelter of the innumerable animals which 

 live in the same pools. I did not find Ulva Linza here, although 

 it is found abundantly on other parts of the coast. The Ulva 

 passes readily down into deeper water, and maybe found on rocks 

 and in the pools of the third zone, but although it grows well 

 there it is yet neither so beautiful nor so luxuriant as it is in its 

 own natural home. 



The most abundant genus however of the order Ulvacea? to be 

 found in this zone is that of Enteromorpha. I found the four 

 species, E. intestinalis, E. comjjressa^ E. clathrata and E. Hojj- 

 kirkii with their various forms growing in profusion in the pools, 

 and on the shores on places where fresh water was ])resent. The 

 upper part of their fronds float on the surfaces of the pools, after 

 the manner of fresh water confervse, and are, like them, inflated 

 by the oxygen which their fronds rapidly eliminate. The api- 

 cies of these plants are frequently blanched and much decayed 

 from exposure, their color is also of a lighter and more yellowish 

 tinge than is that of the Ulva. The last species E. Hopkirkli is 

 rare both in America and in Europe, and is readily known by the 

 confervoid articulation of its ramulae. Along with these, an 1 firmly 



