Notes. 
649 
into a colourless attaching-disc or a branched rhizoid. Three years ago, Schefferle 1 
described the development of a young plant with this type of basal cell in Oed. 
rti/escens, Wittr. ; his account is as follows : — ‘ In der Membran eines festgehefteten 
Keimlings wird in der Mitte der dem Substrat abgewendeten Flache, am Scheitel der 
Wolbung, durch einenKreisriss ein kreisrundes, 4/xim DurchmesserhaltendesMembran- 
sttick (eine ‘Kappe ? ) herausgeschnitten. Durch die so entstandene Offnung wachst nun 
der Keimling, gleich einer keimenden Pilzspore, zu einem Schlauch aus, den Oedo- 
goniumfaden bildend (Taf. XXXI, Fig. 4) Die erste Theilung, welche die Sonderung 
der ersten cylindrischen Zelle des Fadens von der halbkugeligen Fusszelle zur Folge 
hat, geht demnach — wie es scheint — wie bei Bulbochaete , ohne Ringbildung vor sich ’ 
(loc. cit. p. 559). 
In the species of Oedogonium 2 , which forms the subject of the present note, and 
which I have had under observation for two years, the lowest (attaching-) cell can 
scarcely be designated hemispherical. Although occasionally slightly flattened on 
one side, the usual shape is decidedly spherical or oval (Fig. 61 b, e, g). The majority 
of these young plants were growing loosely attached to the sides of a glass vessel, 
frequently in large clusters (Fig. 61 g), and yet the side turned towards the substratum, 
was generally rounded off ; this indicates the necessity of some means of attachment 
other than pure adhesion, and, as will be shown subsequently, such really occurs. 
The basal cells contained abundant chlorophyll and numerous starch-grains, like the 
succeeding cells of the filament, and, like these, showed two well-marked layers in 
their wall 3 . 
I have not been successful in observing the actual course of the first cell-division 
in these young plants, but an examination of two-celled stages affords no data which 
do not agree with those of Schefferle (loc. cit.) ; the cap, which is detached before the 
contents are protruded to form the filament, is frequently still to be met with at the 
apex of the young plants ; in other cases it is absent, having undoubtedly been lost in 
the surrounding water. There seems to me, however, little difference between this 
type of division and that which Poulsen 4 has described for the first cell-division of 
the young plants of a species of Oedogonium , and which 1 5 have subsequently found 
to' occur regularly in Oed . cardiacum and in some cases in Oed. stagnale. This type 
of division is mainly due to the fact that the new cell-wall substance is not confined 
to an annular ring, but occupies a dome-shaped area in the upper portion of the 
original (basal) cell. This leads to the detachment of the entire apical portion of the 
cell- wall as a cap or lid. The curious shape of the basal cell in these species of 
1 Einige Beobachtungen iiber Oedogonien mit halbkugeliger Fusszelle. Ber. Deutsch. Bot. Ges., 
vol. xix, 1901, pp. 557-563, Tab. XXXI. 
2 I have unfortunately omitted to determine this species, although it produced oogonia during the 
past year; the measurements are as follows: — diameter of filaments = 10-15 ju; length of cells = 
2 7-33/*- 
3 Prof. G. S. West very kindly informs me that in Oed. Howardii Nov. Spec. MSS., there is a 
similar basal cell, to which the description 1 hemispherical ’ scarcely applies. Hirn’s (loc. cit.) Fig. 
VI A shows some indications of more than a merely hemispherical basal cell. 
4 Om svsermsporens spring hos en art af slaegten Oedogonium. Botan. Tidsskrift, 3 0 ser., vol. 
ii, 1879, p. 1. 
5 Structure and Development of the young plants in Oedogonium Ann. of Bot. vol. xvi, 1902, 
pp. 477-8. 
