102 THE RELATION OF PLANTS TO TIDE-LEVELS 
evergreen, slightly fleshy perennial, about 7 to 9 dm. in height. It does not 
occur in distinct rows or lines, but singly or in small clusters, and its distribu- 
tion is much more independent of soils and tide-levels than that of Cakile. The 
frequency of the plants may best be illustrated by referring to the map of the 
area studied by Professor Conard (plate x1v), and also by noting the fact that 
75 plants of Solidago were found between 400 and 600 west, on the south slope 
of the Spit. A similar abundance is found at 100 to 200 east, on the top of the 
Spit, and from 900 to 915 west at 9.5 to 10 feet. From 0 to 200 west this 
goldenrod is very scarce across the whole width of the Spit, except for one patch 
of 20 plants on the south slope at 9 feet (see plates v and x11). Solidago, 
when above the 8-foot level, is a deeply-rooted plant, which draws its water- 
supply from the constantly damp layer of the sand far below the surface. 
EHuphorbia polygonifolia, the fourth species of this belt, is a small, spreading, 
deep-rooted plant that is scattered quite sparsely along the nearly bare sand of 
the north shore of the Spit, chiefly between 9 and 10 feet, at and below the 
margin of the Ammophila. It occurs still more rarely along certain parts of 
the south side, at about the same levels. (See plates v and x11i.) This species 
is so small and the individuals so scattered that it plays no conspicuous part in 
the make-up of the plant covering of the Spit. 
Lathyrus maritumus is another species which is much less abundant here 
than on the more exposed beaches of the Outer Harbor and Sound. It isa 
spreading, rather fleshy-leaved, creeping perennial, with buried stems running 
widely and deeply through the soil. Only a few dozen scattered clumps are 
present on the Spit, and these are chiefly on the north side of the western half, 
near the 11-foot level. 
Aanthium echinatum, a broad-leafed annual composite, is another plant 
common on the more exposed shores of Long Island Sound, which occurs some- 
what sparingly on the Spit. It is found chiefly on the top and the north side, 
‘from 400 east to 400 west, at 10 to 11.5 feet. In a number of places in this area 
groups of from 2 to 6 plants are scattered quite frequently. Isolated plants 
are found occasionally on the south shore of the Spit, sometimes down below the 
9-foot level. (See plates v and x11.) 
Salsola kalt is a small-leafed, fleshy annual, single plants of which are found 
just above the line of trash from summer tides at the 8.5-foot level on the north 
shore of the Spit, e. g., from 400 east to 400 west. A few dozen plants altogether 
may be found at other places on the Spit, as toward the top at 11 feet or along 
the south shore near the 9-foot level. 
All of the last four species are characteristic of the sandy beaches of the outer 
harbor, where the higher waves form a wider storm-beach, but even here they 
do not form dense and continuous growths. The chief and perhaps the sole 
reason for this is the dry and unstable nature of the substratum in which the 
plants grow. It seems clear that there must be very little real competition with 
other species in the case of most individuals of these species that do finally 
succeed in getting rooted, clear of the active waves. In plants so sparsely 
scattered there is no injury by shading, and it is only in the cases of older plants 
with extensive root-systems that there can be any appreciable competition for 
water underground. ‘There can certainly be no accumulation of injurious, 
excreted waste about the roots of any species in a soil so porous and frequently 
flushed. 
