49 2 Campbell . — The Development of 
made during October, November, and December, which is 
probably the natural period of germination. Those started 
later germinated less promptly, and in most cases failed to 
develop perfect reproductive organs. Where the tubers were 
placed in earth at once, they failed to germinate, at least 
early in the season, but what the explanation of this is it 
is difficult to see. It was found best to allow the tubers to 
remain in water until growth was well commenced, and then 
to transfer them to earthen saucers filled with sandy soil 
similar to that in which they originally grew. These saucers 
were placed in others filled with water and the top covered 
by a pane of glass. In this way abundant moisture was 
supplied, but evaporation was not prevented, as is the case 
under a bell-jar, and the plants grew much better than when 
grown in an absolutely saturated atmosphere. 
As soon as the tuber is placed in water it absorbs the 
moisture rapidly, and the activity of the cells in the apex is 
almost at once resumed. Within two or three days the cells 
of the growing-point usually show more or less chlorophyll, 
which is quite absent from the cells of the ripe tuber. With 
the development of chlorophyll there begins an active growth 
in the apical region, which grows out into a green shoot which 
is very soon recognized as the first stage of the young thallus. 
This shoot is somewhat heart-shaped when seen from above 
(Fig. 5), and its margin is strongly fringed and lobed. From 
the lower cells numerous fine rhizoids with delicate, colourless 
cell-walls grow out, and, if the plant is now placed upon 
earth, quickly fasten the young thallus to the ground. As 
the thallus develops, the supply of reserve food in the tuber 
is rapidly exhausted, and the tuber finally decays. As it is 
very easily broken off it was overlooked when the plants were 
first discovered. 
As the plant grows, there are formed from the margin 
structures which can only be designated leaves. These are 
formed in regular succession on either side of the growing- 
point, and recall strongly the similar organs in Fossombronia 
or P etalophyllum . These leaves are very conspicuous, espe- 
