248
Dr. Roth's Observations on the
Rivulante
a gelatinous transparent substance, without any membra­
naceous covering. N o t being provided at that time with a
compound microscope, we were unable to discover any
thing in the substance but dark branched lines, which we
took for the organs of fructification. To this want of a
good microscope it was likewise owing that we overlooked
the hair-like threads I afterwards discovered on the outer
surface of this plant.
T h e following day we found in a small ditch in a mea­
dow, likewise on pebbles, a second species, RJVULAIUA
confervoide.s*.
This, in regard to structure and substance,
agreed with the former ; but it was much smaller, more de­
licate in all its parts', and its surface beset with very thin,
transparent, geniculated, and branchy threads.
Two years after, being on a botanical tour with the Rev.
M r , Trenlepohl, I found, at the borders of an extensive lake
in fhe duchy of Oldenburg, a third species, R I V U L A R I A
endiuicvfoliai, on withered sprigs and roots. - It very much
approached to Rivularia confervoides, from which it was,
however, sufficiently distinct by its outward appearance and
internal structure.
I n the summer of 1 8 0 ) I found this latter species very
frequently, and in different stages, on the stalks and leaves
of Myriophyllum verticillatum in a ditch of a meadow, and
intennixt with it several round g'o'i.ules of a-green colour,
which at first view I took for Tremefla verrucosa in a j u v e ­
nile state : a more exact examination, however, that proved
them to be without a membranous covering, occasioned
me to give up this idea, especially as, except in their round
shape, they very much agreed with the Rivulariae. At the
same time I discovered, in the transparent substance, arti­
culated threads which I had not yet seen so distinctly in the
other species; a circumstance that induced me to subject
* Tentamen Florae Germanics, I. c. p. 5-35.
+ Ibid. p. 54fi.
them