Fritsch, Observations on the young plants of Stigeoclonium Kütz. 369 
which an irregularly branching filament, creeping: on the substratum, 
is formed. From the cells of the procumbent portion further ver- 
tical branches subsequently arise. This type of development he 
found in Si. variabıle and St. flagelliferum. — In the second case 
the germinating zoospore grows out on both sides to form a creep- 
ing filament, which branches several times on the substratum; from 
the basal portion thus formed all the vertical branches arise. To 
this second type Berthold reckons 8%. Zubricum and Sue undeter- 
mined, strongly-branched species. 
In 1891 Gay published his „Recherches zur le developpement 
et la classification de quelques Algues vertes“, in which Sizgeo- 
elonium is discussed rather fully. He remarks in connection with 
the two modes of germination, described by Berthold (cp. Gay 91, 
p. 41):* Les deux modes de germination des zoospores decrits par 
M. Berthold s’observent notamment chez le Stigeoclonium variabıle. 
La macrozoospore (fig. 45) se fixe par son extremite etroite; les 
quatre eils disparaissent. La plantule unicellulaire prend une forme 
allongee, attenude aux deux extremites; elle possede encore le point 
rouge dit oculiforme (Fig. 46). Dans la plupart des Chaetophorees, 
V’aceroissement se continue uniquement par l’extr&mite superieure 
de la cellule qui donnera naissance par des cloisonnements successifs 
au thalle vegetatif; l’extremite inferieure forme l’appareil fixateur; 
c’est ainsi que les choses se passent, par exemple, chez le Si:igeo- 
- clorium amoenum (fig. 47). Il n’en est pas de mäme chez d’autres 
especes. Chez le Stig. variabıle') la plantule unicellulaire s’allonge 
a la surface du substratum par ses deux extremites, qui sont le 
‚siege d’un accroissement d’egale valeur. Il se forme ainsi une sorte 
de rhizome (fig. 48, 49 et 50), dont les cellules courtes, plus ou 
moins renflees, emettent des rameaux dresses. (Ceux-ci donneront 
naissance aux thalles vegetatifs.....“ Gay’s figure 47c, representing 
a young plant of Si. amoenum, cannot be said to show an „appareil 
fixateur“, since the lowermost cell of the upright filament only differs 
from those above it in having a somewhat irregular shape. Neither 
is the basal cell of the simple, upright young filament in any 
way modified in the young plants of Stig. insigne, figured by Nägeli 
(55, Tab. I, figs. 18—22). Nevertheless Berthold (78, p. 200) 
thinks it possible, that these figures merely show early stages in 
his first type of development. I shall return to this subject below. 
In the year immediately succeeding the appearance of es S 
treatise, Huber published a paper (Huber 924, p. 322, 323), in 
which he remarks that „beaucoup d’especes de Stigeoclomium forment, 
en germant, un rhizome rampant „plus ou moins ramifie, sur lequel 
naissent des rameaux dresses, qui se ramifient & leur tour et con- 
stituent le thalle dresse* (Berthold’s second type!). 
In the same year Huber published a second paper entitled 
„Contributions a la connaissance des Chaetophorees Epiphytes et endo- 
phytes et de leurs affinites.“ Here (Huber 92®, p. 274, etc.) & 
') Inasmuch as Gay commences this paragraph with the remark that the 
two kinds of germination of the zoospores, described by Berthold, may be 
observed in St. variabile, it is remarkable that in what follows he’ ey de- 
scribes one method for this species. 
