THE DISTRIBUTION OF BEACH PLANTS 
Epita A. ROBERTS 
The following observations were made of the distribution of 
plants on the lower and middle beaches of the coasts of the 
Elizabethan Islands and Falmouth. The Elizabethan Islands and 
Falmouth are situated in eastern Massachusetts, Falmouth being 
a part of the mainland, and the islands extending in a chain into 
the ocean, bordered by Buzzard’s Bay on the west and by Vineyard 
Sound on the east. 
The facts here noted were observed while I was collecting 
material for the investigation of the osmotic pressure of succulent 
plants in the above-named localities. A more or less definite 
grouping of the succulents was found, and, when present, certain 
plants were always in advance, where they would the more often 
be covered by the salt water. Later investigation will attempt to 
show whether the different locations on the beaches present more 
or less difficult situations for maintenance of growth, and, if so, 
whether there is a greater or more variable osmotic pressure among 
the forms to account for their being able to occupy more adverse 
situations. Competition of species cannot account for the presence 
or absence of forms, for GANONG (6) has shown that the ground is 
not already occupied, therefore the struggle must be with the 
physical environment. 
Thirteen locations were selected as affording types of all shores 
on the Islands and Falmouth where succulents might be found. 
These may be divided into sea beach and sea cliff types. The 
coasts of the sea beach type are readily divided into lower, middle, 
and upper beaches according to Cowtes (4). The upper beach 
in all cases is a low dune, back of which there is always found a 
pond. The dune at Chappaquoit Point is the highest. 
The sea clifis may be divided into two classes: those at whose 
base the rise and fall of water varies so little that a zone of Zostera 
marina is present and those at whose base this plant is absent. 
The sea beach type was found at Chappaquoit Point, Falmouth 
Botanical Gazette, vol. 60] [406 
