469 
the young plants in Oedogonium. 
within the mother-cell (Fig. 27, c ). A branched, root-like 
organ had been formed at the one end, but the reverse end 
did not bear a tip as in the normal condition. It is worthy 
of note that the polarity of the inner individual is just dia- 
metrically opposed to that of the mother- cell (cf. Poulsen, 
* 7 9, p. 2). Usually, however, if unable to escape, the contents 
of these young plants die off. 
The cells of the young plant have the chlorophyll arranged 
in longitudinal bands in the manner characteristic of the adult 
cells of Oedogonium . Several large pyrenoids (/in Fig. 26, 
a and b ) are present in each cell, being closely surrounded by 
numerous starch-grains. The nucleus — a large rounded body, 
about twice the size of a pyrenoid, and generally parietal in 
position — often shows up well without staining (cf. Fritsch, 
1902, Fig. 23, f\ especially in plants which have been kept 
indoors for a few days. With Chlor-zinc-iodide the walls of 
the cells and the tip, which in the fully developed young plant 
appears quite solid, stain blue ; the same colour is taken on 
by the basal disc. In all the species of Oedogonium examined, 
I found the cellular structure of the young plants to conform 
to the above description, except that in some of the smaller 
species (e. g. Oed . calcareum) the cells have only one pyrenoid 
apiece. The arrangement of the chlorophyll also varies 
slightly — apparently only irregularly though, and according 
to external conditions. 
The young plants in Oed. capillare were found to possess 
two chief types of root-ends : the first strongly branched and 
expanded chiefly transversely to the Jong axis, the second 
slightly or not at all branched, and greatly elongated in 
a longitudinal direction. The first type — the attaching-disc 
(Fig. 25, n ) 1 — was mostly to be found in the young plants, 
which were attached to a firm substratum (such as the sides 
of the vessel) ; the second type, on the contrary, occurred 
invariably in the young plants floating on the surface of the 
water or in such as were not attached to any definite object 
(Figs. 25, a and 26, a ). It is a fact that Wille (’87, p. 456) 
1 Cf. also Fritsch, ’02, Fig. 23 /. 
K k 2 
