Fritsch, Observations on the young plants ot Stigeoelonium Kütz. 379 
on each cell; these do not however according to him exist simul- 
taneously, but succeed one another, a new hair being formed, when 
the old one gets broken off, so that ultimately there may be seve- 
ral hair-bases to each cell. To a certain extent this is also the 
case in my species, although I frequently saw two fully-developed 
hairs on a cell. Huber’s A. repens and the form, that I am dis- 
eussing, differ from the typical A. repens Braun, which has small 
cells, which are transversely stretched and in which a single hair 
is inserted at the extremity of each cell (cp. Wille 90, p. 95, Fig. 
58A). I have not yet settled upon a suitable name for the new 
species, which shall, however, be named and described shortly. 
The Aphanochaete question has caused me to diverge from the 
epiphytic species of Stigeoclonium, with whose description I commen- 
eed this part of my paper. I propose now to discuss the affinities 
of this latter form. 
Berthold (78, p. 201) was the first to describe an epiphytie 
Stigeoclonium with a strongly-developed base. The zoospore here 
germinates according to Berthold’s second type, but .‚die junge 
Sohle verzweigt sich von Anfang an sehr reichlich, aus einer Zelle 
entstehen häufig drei, sogar vier Zweige.“ 'This results in the for- 
mation of a pseudo-parenchymatous disc, whose cells are arranged 
in radial rows. The upright branches, which are developed from 
the cells of this disc, are closely placed and are occasionally 
branched (loc. eit. Tab. 2, fig. 4). Between these branches are 
seattered long septate hairs, which originate basally from a cell 
with a small quantity of chlorophyll. This is the Sig. faretum of 
Berthold. 
In 1858 Möbius (88, p. 239) describes an epiphytic Stäigeo- 
elonium, growing on the leaves of Potamogeton occidentalhs; this 
species forms „Coleochaete-ähnliche Scheiben, welche einen Durch- 
messer bis zu 0,5 mm erlangen können. Die Scheiben entstehen da- 
durch, dass die vom Mittelpunkt nach allen Seiten ausstrahlenden 
Fäden mit ihren Verzweigungen in einer Ebene und ziemlich dicht 
nebeneinander liegen (Fig. 3a, Tab. IX).“ The cells then grow out 
into short (1—3 celled) upright branches, which are apparently un- 
branched, and which in a few cases were seen to terminate in & 
eolourless hair. No name is given to this plant, which is described 
as Stigeoclonium Spec.; nor is reference made to Str. Farctum 
Berth. 
Finally Hansgirg (86, p. 69) described a new species, Stigeo- 
clonium pygmaeum,,in which the ‚niederliesende, dem Substrat 
fest angedrückte Aste zu Coleochaete-ähnlichen, unregelmässigen 
Scheiben verwachsen.‘ The upright branches, whose cells attain 
only about half the diameter of those of the base, are generally 
branched immediately above the base; the branches often terminate 
in hairs. The Alga, which grows epiphytically on (more rarely endo- 
pbytically in‘) Lemna minor and various other aquatic plants, is 
strongly encrusted with calcium carbonate. Hanseirg later (93, 
p- 217) unites Stig. pygmaeum with Stig. faretum Berth. as var. 
pygmaeum Hans2. 
Iı cp. the fourth part of this paper, p. 13. 
