By wao^ of review it may iDe well to point out that eelgrass ( Zostera 

 marina) is a subaergad pondwEed (Haidaceae) growing on tida]. mud flats and 

 estuaries along tloe coast in water fix)m the mean lo":? tide level to a depth 

 of 10 feet or mure at low tid.e. Its range on the Atlaiitic coast is from 

 Bogae Sound and New River in southern Ilorth Carolina north'vard to southern 

 Lahrador, with outlying nore northerly stations in James Bay and southern 

 Greenland. The ssir& species IJiewise occurs on the European coast from 

 the Meditop^rcnean Sea northTrard to northe^i'n Scandinavia. Tbls species 

 with a numoer of varieties is found aj.so on "both the ijnerican and the 

 Asiatic sides of the Pacific. It is significant that the plant is still 

 unaffected in Pacific waters, while on "both the Ainerican. and the European 

 sides of the Atlantic most of the eelgrass "beds have "been practically 

 denuded since 1931. 



Plants of Zostera from different localities on the Atlantic coast 

 vary greatly in size and general ^pearance. Some of them along the coast 

 of Maine may have leaves more than 2 yards long and half an inch wide. 

 Prom Maine southward, the plants show an irregular, though none the less 

 definite, reduction in size until in coastal North Carolina the leaves of 

 some are only 5 or 6 inches long and proportionately narrow. 



Preserved specimens of eelgrass group nicely on the "basis of size 

 into fairly distinct regional varieties. Further study shows that each 

 region so indicated comprises a more or less definite coastal unit having 

 quite similar ecological conditions. Preliminary study of older specimens 

 in the Gray Herharium a.t Cambridge tends to "bear out the reality of this 

 division of the range of Zostera into ecological units. 



PEESMT CONDITIONS 



Maine and New Hampshire 



The coast of Maine and New Hampshire south to Great Bay is charac- 

 terized by extreme ranges of tides, cool or cold water during a large part 

 of the growing season, and a tremendous extent of shore line broken up into 

 innumerable coves and bays. These bays are frequently shallow and have 

 suitable bottom conditions for the growth of Zostera . The normal plant for 

 that part of the coast is robust, the leaves often being 6 feet long. Prob- 

 ably a variety of ecological conditions contributes to the prodo.ction of 

 this large type of plant. The tendency of Zostera to expend its energies 

 in vegetative activity as long as the water remains too cool to permit 

 flowering may have some influence. In his monograph, Setchell 2/ concluded 

 that vegetative growth would commence after the period of "recrude scent 

 rigor" when the temperature of the water was 10° C, whereas flowering and 

 fruiting could not take place until the water temx)erature registered between 

 150 and 250. 



The progress of one particular colony of eelgrass at the moath of 

 Great Bay, N. H. , was followed rather closely this past season. When first 

 observed in April the bed conrprised fairly extensive stands of fine, 

 heal thy- appearing plants, these being quite solidly grouped in places. The 



2/ Setchell, W. A. Morphological and Phenological Notes on Zostera 

 marina L. Univ. Calif. Pub. Bot. 14: 389-452, f. 1-59. 1929. 



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