410 Rennert: THE PHYLLODES OF OXYPOLIS FILIFORMIS 
none of the difficulties of absorption of the liquid in bogs. These 
submerged individuals as well as those in the bell-jars were seen 
to undergo true aquatic adaptations consisting in the loss of hypo- 
derm of the central stellate tissue and of the glands; the reduction 
of the chlorophyl-bearing elements, of the endoderm, and of the 
number of stomata as well as of the xylem; the change in the 
position of the resin duct ; the modification of the epidermal cells, 
stomata, cells of the septa and the course of the bundles through 
the septa; and the adoption of a new method of propagation. 
These changes may be divided naturally into two classes, those 
which involve a suppression of xerophytic characters and those 
which are a means of adaptation to moist conditions and therefore 
hydrophytic in their nature. In the first class we must consider 
the loss of hypoderm and glands, the reduction of palisade-cells 
and water-storage tissue of the endoderm and the loss of cuticle ; 
while we find in the modification of the epidermal cells, the re- 
duction and modification of the stomata and the adoption of a new 
method of propagation types of structure peculiarly distinctive of 
hydrophytes. If the action of water free from high concentration 
of osmotic substances will induce such sweeping departures from 
the normal, it seems but reasonable to conclude that the plant is 
naturally a swamp xerophyte. 
The adaptations described seem to have been most thoroughly 
adopted by the species since the characteristic structure of the 
phyllodes is to be found in the seedlings. These seedlings were 
raised from seed developed by the plants with which the ex- 
periments were made. The cotyledons were flat and linear in 
shape and 5 to 6 cm. in length. When the first leaf developed it 
exhibited the typical awl-shaped, septate character and bore glands 
and the accompanying scales along one side throughout its length. 
In internal structure it also resembled the later leaves in all re- 
spects, except that the hypoderm was absent and that the cells of 
the endoderm bore chlorophyll. 
The chief results of importance brought out in the foregoing 
ney may be briefly summarized as follows: 
. The leaf-structures of Oxypolis filiformis are terete, aw!- 
es phyllodes with numerous septa or diaphragms, and this 
form is exhibited even by the first leaf of the seedling. The 
sich. 
