OP CEYLON AND INDIA. 
369 
anisolobous fruit with one deciduous valve. The stigmas 
in the Atgaon form are generally subulate, but in the var. 
Willisiana are very often ovate or almost cordate, notched 
or even fimbriate or divided into two, like the stigmas of 
the Hydrobryums to be considered below. The ovary wall 
shows no vascular bundles, and the fruit consequently no 
ribs (PI. XXIV., fig. 9), but, as fig. 10 shows, it has a stout 
cutinized inner epidermis like that in the preceding genera, 
then a layer of thick- wailed cells (f ), and outside that one 
or two layers of sclerenchyma, followed by the outer thin- 
walled epidermis and sometimes a thin-walled hypoderm. 
The thin-walled cells fall away from the ripening fruit, 
which has a smooth wall. 
I have seen no evidence of rejuvenescence, but it probably 
occurs as in Dicræa, 
Comparing this genus with the preceding ones, it is 
evident that it is very similar to Dicræa, so far as morpho- 
logical adaptation to its mode of life is concerned ; it has 
the same algoid form of thallus and reduced secondary 
shoots. Its chief interest is in the great polymorphism, 
probably the most extreme known among the higher plants, 
and in the fact that this carries out to its highest develop- 
ment what we saw begun in Dicræa. Strange though the 
forms of the various thalli are, regarded only as structures 
in flowering plants, they are parallel to the similar forms 
that may be found among the algæ of moving water, just 
as is the case with nearly all the other forms assumed by 
the Podostemaceæ. 
WILLISIA, 
[Warming- ; Willis, Rev. Pod. Ind., Ann. Perad., I., p. 233.] 
This very peculiar genus, so far as at present known, is 
confined to the Anamalais and Burma ; I have collected 
material in the former locality, and Mr. Barber has since 
obtained some for me from the same place at an earlier time 
