TAYLOR: WHITE-CEDAR SWAMP AT MERRICK, LONG ISLAND 83 



tension zone, for here, crowded in a small area, are two groups of 

 species, three quarters of the woody plants of which are southern 

 and three quarters of the herbaceous plants northern. 



The conviction that these cool-atmosphere, typically northern 

 herbaceous species are found in the cedar swamp merely because 

 the environment is favorable and not as the result of some far 

 reaching, almost catastrophic agency, seems inevitable. That 

 the large percentage of herbs should be northern and that an 

 equally large percentage of woody plants should be southern, 

 does no violence either to the theory of Sinnott and Bailey as to 

 the origin of herbaceous angiosperms, or to the observed ratios 

 of growth-forms as worked out by Raunkiaer. The chief sig- 

 nificance would seem to lie in the fact that the occurrence of these 

 northern herbs at this point, and probably at other shaded swamps 

 on the island, is conditioned by a group of southern woody species, 

 which have failed to bring with them from the south the herbs 

 ,with which they are there associated. And just because these 

 southern woody plants have created a favorable habitat we find 

 in their shade a growth of northern herbs, which, needing such 

 conditions, are likely to occur there and nowhere else. This 

 looks like a commonplace way of accounting for the mingling of 

 two such diametrically opposed elements in the same swamp, but 

 Chamaecyparis swamps further south seem to indicate that the 

 southerly range of a number of northern herbs is conditioned by 

 the occurrence of these swamps. Upon this conception the 

 distribution of the tree is of less significance than is the fact that 

 its occurrence postulates conditions favorable for the growth of 

 herbs that would not be there if the Chamaecyparis was lacking. 

 And the white cedar does, to a peculiar degree, make unusual 

 conditions on the coastal plain, the dense cool shade being in 

 such marked contrast to the surrounding region. 



The WHITE CEDAR AND THE SALT MARSHES AT MeRRICK 



Near the lower end of the cedar swamp, the trees begin to 

 thin out, both as to frequency of occurrence and size, and im- 

 mediately facing the salt marsh there is a large area made up of 

 dying or wholly dead Chamaecyparis trees. See plate io. 

 Facing these is the salt marsh, which is nearly two miles wide. 

 There is one good-sized tidal stream in it having near its upper 



