104 THE AMERICAN NATURALIST. [VoL. XXXVI. 
lime-impregnated stems, made flexible by being broken into 
short joints, and constricted between the joints like a string of 
coral beads ; and they form an intricate, often turf-like, growth 
over the wave-washed rock. 
We could not imagine a better opportunity for Phyllospadix 
in search of a lodging place; and it seems that Phyllospadix is, 
in fact, not slow to catch on, for experience showed that the more 
profitable way to collect Phyllospadix seed was to search at low 
tide, not in the eelgrass itself, but rather among the corallines 
covering some flat rock just inshore from the eelgrass beds. 
When the fruit, hurried landward by a wave, blunders 
against a tip of Amphiroa, there is a fair chance that the 
stem will slip into the crotch of one of the arms. When 
once this has happened the wanderings of Phyllospadix are 
over, The many barbs unite to hold whatever is caught, and 
further knocking about by the waves only serves to wedge the 
alga more tightly into the grasp of the seed. The segmented 
structure of the Amphiroa prevents it from slipping through 
the grip of the arm, and so the seed is safely planted, as it 
were, in a tree-top. Frequently it even catches two branches 
of its host, one in either armpit, and so 
swings secure on two anchors. 
Time and seed are now ripe for ger- 
mination. What next takes place will 
be better understood upon referring to 
Fig. 5. Here is a longitudinal, dorsi- 
Fic. s- — Diagram of dorsiventral ventral, median section of the immature 
median section of Fig.2. c,coty- 2 
edon; i, insertion of pistil; fruit. The cavity of the seed is filled 
tie by the embryo, af which the bulk cor- 
sists in the hypocotyl (%, ^). The coty- 
ledon (c) is short, straight, and tubular, and serves merely as a 
sheath for the plumule (^). It lies upon the ventral side — 
as regards the pistil — of the hypocotyl, and points toward the 
base, t.e., in the direction of the arms. The testa (7) is formed 
of a single layer of cells with thick, lignified cell walls, and 
thus, while it serves, like an arch of bricks, to protect the 
embryo from outside pressure, it is readily burst open by the 
-~ swelling within of the hypocotyl. — 


