MS WILLIS : MOilPHOLOGY OF THE PODOSTEMACBÆ 
formation ; these grow along horizontally for a short distance, 
and then give rise to vertical branches, exactly as the 
primary thallus does. PL XX., fig. 1, shows a piece of reju- 
venescent thallus from a plant which had been submerged by 
a rise of water in the fiowering season before it was actually 
dead. As the water falls in the dry weather, the lower parts 
of the plants usually exhibit a large amount of this sort of 
rejuvenescence, and towards the end of the dry weather 
there is usually quite a large crop of plants with floating 
roots from 5 to 8 inches long growing upon the rocks. These 
roots show no sign of transforming their leafy shoots to 
floral shoots the same year. 
This species is well represented in the herbaria, but the 
leaves of the shoots at the outer end of the thallus are very 
brittle when dry, and have very often disappeared, some- 
times even the whole of the foliiferous portion of the thallus 
is missing. When this is the case it is perhaps usually due 
to the fact that the specimens were gathered when the fruit 
was ripe, by which time the terminal portion of the thallus 
has usually disappeared, having withered up and broken oft'. 
The leafy tips of the bracts, too, fall away to a large extent. 
The size of all parts varies greatly. E.g.y the pedicel of the ripe 
fruit, described as 1/5 inch long by Trimen, 6-8 mm. by 
Weddell, 8 mm. by Tulasne, varies in the specimens in the 
Peradeniya herbarium from 3 to 9 mm,; perhaps 6-7 is the 
most usual length. The flower bud varies much in bulk, 
and also the fruit, which varies from a length and breadth 
of 2*2 and 1*25 mm. to 1*5 and *75 mm.; the largest fruits 
are thus four times the bulk of the small. Some specimens 
recently found in the Bambarabotuwa river, a tributary of 
the Kalu-ganga, in Ceylon, by Mr. H. F. Macmillan, show a 
smaller habit altogether. The floral shoots in many of the 
specimens are only monostichous. The bracts also vary in 
the direction of the more cowl-shaped form of those of P. 
algæformis. 
