390 WILLIS : MORPHOLOGY OF THE PODOSTEMACBÆ 
in this condition till a little while before the beginning of 
the north-east monsoon in October, when they mostly 
become trausformed into flowering shoots during the rainy 
weather which lasts through the remaining part of the year, 
till when the water falls in January only those near the 
margin of the thallus still retain their leafy condition. The 
flowering shoot consists only, as a rule, of a terminal flower 
with a few bracts below it, and lies horizontally upon the 
thallus, thus showing a dorsiventrality, which is absent in 
the younger stages. The growing points, too, are then above 
the surface of the thallus. PI. XXXIY., fig. 6, shows stages 
in the transformation of leafy to floral shoots, which is very 
similar to that already described in Dicræa. The floral shoot, 
as was mentioned in describing the dry season appearance 
of the plants, points towards the edge of the thallus. The 
sheathing bases of the leaves now produced enlarge and 
become fleshy, and presently the tips wither and fall off, 
leaving the swollen basal parts of the leaves, which then 
form the scales or bracts of the floral shoot. These scales 
show a distinct dorsiventrality, in that they are very much 
thicker in the exposed portions upon the upper than upon 
the lower side ; the latter is quite thin and membranous, 
while the former is thick and fleshy. This difference is 
much less in species like Dicræa elongata, where, though the 
shoots have an upper and a lower side, both are freely 
exposed in the water. 
At the tip of the floral shoot the flower develops, enclos- 
ed in its spathe, and it is fully formed in all its parts early 
in the north-east monsoon, though, perhaps for want of the 
necessary food supply from the thallus, it seems incapable 
of further development and anthesis in the event of the 
water-level falling prematurely before December. 
Should the fall of the water be somewhat early, specimens 
may frequently be found in the condition shown in PI. 
XXXIY., fig. 6, with the long green tips still persistent upon 
some of the bract-scales, and in the specimens of Podostemon 
Gardneri preserved in the herbaria this state of things is 
