Observations on the young plants of Stigeoclonium 
Kütz. ’) 
by 
F. E. Fritsch, B. Sc., Ph. D. (Kew). 
(With plates XI, XI.) 
1. Introductory remarks. 
The early stages in the development of Stigeoclonium are much 
better known, than in many other genera of filamentous Algae, for 
instance Oedogonium, in which the fate of the oospore is still obscure 
in the majority of the species. Little attention had even until 
recently (cp. Lemmermann 98, Schefferle 01 and Fritsch 028) 
been paid to the germination of the zoospore in the latter genus, 
althoush apparently there is sufficient variation in the mode of 
development. This neglect is probably due to the much greater 
interest, attached to the adult structure in Oedogonium, which has 
tended to distract the attention of algologists and to make a very 
cursory description of the germinating zoospore the only information, 
vouchsafed concerning the young plant. 
Several important papers, which contain observations on the 
germination of the zoospores in Stigeoclonium and on the structure 
of the young plants, have been published. Of these a few may be 
briefly mentioned at once: Cienkowski in 1876 in a paper, entitled 
„Uber Palmellen-Zustand bei S’ygeoclonium“ describes the formation 
of the basal horizontal portion?) (Sohle) in Stig. stellare Kütz. (cp. 
Cienkowski 764, p. 18, Tab. I, figs. 1, 2, 3, 9). According to him 
this is formed by the sermination of a number of zoospores, which 
on the cessation of activity had come to lie close together. This 
composite origin of the basal portion has not, however, been confirmed 
by later observations. 
In Berthold’s „Untersuchungen über die Verzweigung einiger 
Süsswasseralgen“, published in 1878 the horizontal portion is de- 
scribed as originating in two different ways (cp. Berthold 78, 
p. 199, etc.; Tab. XV and XVD): in the first case the zoospore ger- 
minates to form an upright filament, from the lowermost cell of 
!) From the Jodrell Laboratory, Royal Botanic Gardens, Kew. 
2) As a rule the young plant in Stigeoclonium consists of a creeping fila- 
mentous portion, from which vertical branches are given off into the sur 
rounding medium. 
