6 2 
M c Nicol . — The Bulbils and Pro-embryo of 
The well-developed whorl of long, single-celled, pointed, stipular leaves 
or bracts occurring directly below the leaves and equal to them in number, 
is characteristic of the plant, as are also the leaflets springing from the 
axils of the leaves. Each leaflet has a sharp-pointed, colourless, trans- 
parent apex, into which the cell-lumen does not enter (Fig. 5 a). The 
stipular leaves measure 2 or 3 mins, in length and are here quite con- 
spicuous, but the small leaves occurring in the axils of the ordinary leaves 
can only be seen on close examination. They resemble the stipular leaves 
in shape, but are much smaller and vary in length even in the same whorl : 
they are generally less than 1 mm. long. In the lower whorls fewer of 
these leaves are formed, there being two or three less in number than the 
leaves. In one case, taken at random, on the lowest nodes of a well-grown 
plant the number of small upper leaves formed varied from one to six in 
a whorl. 
The development of the stipular leaves and of the axillary leaves has 
been studied by Giesenhagen (’02), who has shown that all three whorls, 
leaves, axillary leaves and stipular leaves, arise in a regular manner from 
cells which become divided into three by two horizontal walls. After 
regular subdivisions the upper cell gives rise either to an axillary branch 
or to an axillary leaf, the middle cell forms the foliar leaf and the lower- 
most cell the stipular leaf. 
The plant is monoecious, the oospores, which ripen in autumn, standing 
singly below the antheridia which are of an orange-yellow colour. 
Migula (’97) mentions that the plant may be slightly encrusted 
with calcium carbonate, but in the specimens on which I worked there was 
no encrustation except in the case of the oospores, which showed an 
accumulation of fine granules, but this never extended to the apex of the 
spore, so that to the naked eye the spores appeared greyish in colour, with 
a black apex where the hard, dark-coloured lamella was not hidden by the 
deposit. 
The Bulbils . The plants under observation were grown in large glass 
jars, and being therefore under somewhat abnormal conditions, it is not 
extraordinary that the oospores were generally incapable of germination, 
though many seemed to arrive at maturity. The plants, however, showed 
great vegetative vigour, and reproduced abundantly from the characteristic 
unicellular bulbils which are produced on the roots. Similar unicellular 
bulbils occur in Chara aspera , in which species they have been described 
and figured by Giesenhagen (’ 02 ). 
The tubercles or bulbils are about 1 mm. in diameter, and occur on the 
root node generally in groups of four or five, though larger groups are 
frequently found. They exhibit no rotation of protoplasm such as occurs 
in other internodal cells. 
Mode of Growth of Tubercles. Tubercles may arise either directly by 
