OF CEYLON AND INDIA. 
371 
most of the Ceylon forms, probably lives for a considerable 
period after being exposed, and probably may rejuvenesce). 
The plant grows in a very rapid current at the place where 
I studied it, and the erect shoots were in a state of constant 
and rapid quivering movement to and fro. 
Mature Structure . — The germination and the early stages 
of the life-history of this plant should be of especial interest. 
The earliest stages that are as yet known are those in the 
material collected in November last by Mr. Barber, and 
these are almost as mature as those collected by myself in 
January, but show very well what I take to be the primary 
axis. One of these specimens is figured in PI. XXX., fig. 2, 
and shows at the base the clump of little floriferous shoots 
just described, with two long shoots, one of which is 
broken off, of an entirely different type. These long shoots 
may be as much as 50 cm. long, and are provided with long 
loriform leaves reaching a length of as much as 15 cm. I 
feel almost certain that each of these long shoots is the 
primary axis of a single plant, but as I have found two on 
some of the specimens, chiefly in dry material, and have 
not been able to satisfy myself that there were also two thalli 
I must leave the question for future decision. The ana- 
tomy is quite different from that of the floriferous shoots, 
and very similar to that of the primary axis of Hydro- 
bryum olivaceum. 
This apparently primary axis, whose upper parts I only 
know from the herbarium material, is non -floriferous as a 
rule, though I have seen it with lateral tetrastichous flori- 
feroLis branches. By the beginning of January, to judge from 
the material collected by myself, it has usually died down, 
and is only represented by a more or less decayed stump at 
the base. This stump is often 5-8 mm. thick, and therefore 
much stouter than the floriferous shoots. The primary axis 
bears leaves in a complex phyllotaxy, which I have not been 
able to make out. It is evidently very flexible, and drifts 
out with the current like the shoots of Tristicha ramosissima 
In transverse section it shows a central vascular strand. 
f5U) 
