the young plants in Oedogonium . 471 
great value for the maintenance of the species, since only 
individuals which are able to attain a definite footing are 
capable of further development. However, this is not in- 
variably the case, for sometimes I met with short floating 
filaments of from 5-10 cells, which had only a long rhizoid- 
like process basally (see Fig. 26, a , in which the lower part 
of a 6-celled individual is figured), and later on I even found 
filaments of considerable length with such a basal termina- 
tion. In Oed. stagnate and calcareum this difference between 
the root-ends of floating and attached individuals is also ob- 
served. At the end of the long root-processes (rhizoids) I fre- 
quently found a small, round, hyaline mass, which, according 
to Wille (’87, p. 458) and Pringsheim (’58, p. 55), consists 
of a substance for attaching the plant to the substratum 
(v in Fig. 25, e and /). 
In an as yet undetermined species of Oedogonium 1 2 I found 
the formation of a long rhizoid basally to be the rule, even 
in the plants attached to a firm base (see Fig. 25, <?,/, and /). 
An attaching-disc, found so frequently in Oed. capillare , was 
comparatively rare here (Fig. 25, d and i). These young 
plants also behaved differently to those of the last-named 
species in that many, although attached, had emptied their 
contents as zoospores (Fig. 25,/ and /) ; the larger number* 
however, had already formed 2-3 celled individuals (Fig. 25, e). 
The young plants of this and the other species examined do 
not possess the tip which is so characteristic for those of Oed. 
capillare* , their apex being perfectly smooth and rounded. 
The lid in the species from the river Severn and in Oed. 
stagnate is not always so readily discerned as in Oed . capillare. 
The emerging zoospore seems 3 to have pushed it on one side, 
whilst it still remained attached to the adjacent part of the 
1 Growing in a glass-vessel in the Herbaceous Department, which contained a 
water-moss from the river Severn. 
2 Tips occur at the apex of the filaments in a number of species of Oedogonium 
(cf. Figs, in Wolle, ’87, cited in foot-note 2 on p. 467) ; other species (< concatenatum , 
var. setigerum , Huntii, ciliatum) have the apex of the filaments thinning down 
into a hair (cf. also Chodat, ’02, p. 48). 
3 I did not observe the emission of the zoospores in this species. 
