30 Lang. — Studies in the Morphology and 
In the further growth of the young plant the originally vertical direction 
of the axis appears to be maintained for a short period, although as regards 
the position of the leaves on one side of the stem and the roots on the other 
dorsiventrality is established at once. The dorsiventrality is probably 
related to the position of the three-sided initial cell. After a few more 
leaves and roots have been developed, however, the apex changes its 
direction of growth and bends over ; the further growth of the rhizome 
proceeds horizontally. The change is shown in the outline figure of the 
larger plant in the accompanying figure (Text-fig. 9, b). In the other plant 
(Text-fig. 9, A) the axis, so far as it is well developed, had grown vertically, 
but the tip was curved over and is directed towards the spectator. It will 
be evident from this specimen that the origin of the plant from an embryo 
Text-fig. 9. A, young plant still showing the foot (f) and the primary root (r 1 ) at the base. 
The shoot has grown erect for a time but is now extending horizontally towards the spectator. 
b, similar plant from the side, showing the change from the vertical to the horizontal rhizome. 
The foot and primary root have been broken off. 
is shown not only by the presence of the foot, but by the different position 
occupied by the first root to that of all the succeeding ones. The later 
roots all spring from the ventral side of the rhizome, while the first root 
stands below the first leaf and apparently on the dorsal side of the rhizome. 
The significance of this will be discussed later. The second specimen, 
which shows the change in direction of growth of the rhizome better, also 
had the foot and first root at its base, but this had unfortunately got broken 
off before it was drawn. 
Discussion of Results. 
The preceding account of the embryo of Helminthostachys , though 
incomplete, provides the main facts. It is clear that the first stage of 
development of the fertilized egg-cell exhibits a definite polarity with the 
