MORPHOLOGY OF PHYLLOGLOSSUM DRUMMONDII. 
667 
stratified, and are also pitted; irregular pits are found in the outer part of them, 
which has accordingly a reticulate appearance when seen in surface view ; clearly 
marked pits are also found occasionally near the internal limit of the radial walls 
(fig. 4). These thickened walls give a mauve colour with Schulze’s solution, and are 
not stained by an acid solution of aniline sulphate : it is thus shown that they are 
not lignified. Some superficial cells grow out as root-hairs, which are sometimes cut 
off by a wall from the parent cell (as shown in fig. 3, h). As might have been 
expected, stomata have not been seen in the epidermis of the tuber. An investiga¬ 
tion of the base of the tuber shows that in the mature state this epidermis is 
continuous over it: a longitudinal section of a tuber in course of development shows 
no trace of those characters which are peculiar to the root, a conclusion which is 
equally borne out by the mature structure. 
Passing now to the apex of the tuber, median longitudinal sections show that the 
mode of division of the cells up to the period of maturity is that known as the _|_ 
mode of division.* I have not in any case observed any wedge-shaped cell at the 
apex in this stage of development of the axis (fig. 6). The arrangement of the cells 
as seen in superficial view from without is represented in fig. 7 ; it is suggested that 
the four cells marked ( x ) may be initial cells in this particular example, but it is not 
insisted that this is universally the case. As will be seen later, there is some incon¬ 
stancy in structure of the apical meristem of this plant, and as the number of tubers 
investigated has been necessarily small, I am not prepared to assert that the structure 
of the apex above described is uniform for all mature tubers. Before germination 
there is no sign of formation of appendicular organs, the apex of the tuber is broad, 
slightly conical, and quite smooth. 
Germination of the Tuber. 
The living tubers, which w T ere sent over in the dry state, w r ere germinated with 
success in the propagating pits at Kew; the first plants made their appearance above 
ground about one month after they were sown. The tubers were of very variable 
size, and the character and number of the organs formed depends, in great measure, 
upon the size of the tuber. Thus it has been found that where the tuber is small, 
foliage leaves are formed, together with roots (one or more), and one new tuber; the 
number of the leaves also depends upon the size of the tuber, being sometimes only 
one, where the tuber is very small. Where the tuber is relatively large, sporangia 
are produced, their position and arrangement being as already described by other 
writers ; in this case the tuber will also produce foliage leaves, roots (one or more), 
and one new tuber, as in the former case. As there is a difference in the mode of 
development of the plant, according as sporangia are formed or not, it will be 
necessary to deal with the two cases separately ; it is however to be borne in mind 
* See Prantl, “TTnfcers. zur Morph, der Gefasslcryptogamen.” Heft i., p. 4. 
