294 WILLIS : MOEPHOLOGY OF THE PODOSTBMACEÆ 
way, as the flowers emerged through the water. Frequently, 
however, we find merely a very short one-flowered shoot 
springing from the thallus, and in this case as a rule there 
is no large foot. In specimens from other localities the feet 
are not so markedly disc-like ; in material from the 
Anamalais they are stouter, and more or lesslohed (PL VIL, 
fig. 5). In Mr. Bourdillon’s material, again, and in some of 
Mr. Barber’s, the foot is represented by a comparatively 
long peg-like organ, which projects downwards from the 
thallus, tapering almost to a point, but expanding at the tip 
when it touches the rock, to which it becomes firmly attached 
(PL VIL, 8, 9). 
Mature Structure . — Closer examination of the thallus 
must be made on living material. The dead plant sheds its 
seeds upon the rocks, and germination takes place with the 
onset of the rains. We have no knowledge of the early 
stages in the life-history, or of the primary axis, though 
we may assume that it gives rise to the creeping thalli. 
Inspection of the tip of a thallus shows that it is almost 
cylindrical, about 0*5 mm. thick, and that it has a well- 
marked root cap (PL YII., fig. 2). Taking this fact together 
with that of the endogenous development of the lateral 
branches, we need have no hesitation in regarding the thallus 
as of “ root” nature. The thallus may grow to a length of 
many inches, and is more or less closely appressed to the 
rock. When it touches it, it is fastened by root-hairs, which 
spread out at their tips in the usual way (PL YII., figs. 3, 4) 
and secrete a dark-coloured cement-like substance. A little 
way back from the tip of the thallus the secondary leafy 
shoots may be found in course of development (PL YII., 
fig. 5). In the Anamalai material figured the shoots appear 
in approximate pairs, one on either side of the thallus, 
breaking out endogenously from lateral expansions of it, 
while at the same time haptera or fastening organs develop 
from these expansions, underneath them. As these organs 
will be constantly met with in subsequent descriptions and 
occur in a great many Podostemaceæ, it will be as well to 
