by little. I t is ijerfectly homogeneous; it is but when
it commences to decompose that it takes on a granular appearance
; but it never presents those longitudinal striæ which
I have remarked in th a t of Conferva and Zygnema.
I have not perceived any motion in the granules of the endochrome,
excepting in the case of the rupture of a filament.
The granules escape then in je rk s; they often collect themselves
into pellets, and sometimes the mucilage which accompanies
them forms about them a species of membrane ;
but these masses of granules have never appeared to me
susceptible of organization into reproductive corpuscles ; In a
Avord, never have I seen them germinate.
The solubility of these granules in alcohol indicates their
resinous nature. Sulphuric acid diluted with Avater contracts
them into the centre of the filament to a faint ribbon
of a broAvnish green. When this reagent is employed of
greater strength, the granules resolve themselves into a
mass of a blackish green ; bu t the external membrane resists
the action of the acid. I f recourse is had to ammonia, it
often happens that, hy a phenomenon of endosmosis, the filaments
empty themselves entirely of their granules. This is
seen especially in the spores which have commenced to germinate;
the granules all issue by the extremity of the
filament in germination, and the external membrane, which
Avas not before visible but at the extremity of this filament,
remains entirely empty like to a glass ball. The ammonia
possesses also the singular property of imparting a light pink
coloration, or vinous red, to certain parts of Vaucheria, particularly
to the superior extremity of the spore, when it is at
the instant of quitting the mother plant, and this part is
less furnished Avith endochrome than the rest.
I f I have not indicated up to the present time to AA’hat
species of Vaucheria the observations which I have described
apply, it is because the species of this genus are established
upon bad characters. In truth, the organization of
the spore, such as I have described it, applies to Vaucheria
ovata D. C. = Vaucheria clavata D.C. et U n g e r; for I have
found once, upon the same filament, both this form
and tha t Avhich has been n.amed Vaucheria sessilis. A
little time afterAvards, the same tufts again have given me
Vaucheria hamata, V. geminata, &c. The appendages
tha t Vaucher regarded as the corpuscles, and Avhich served
him to establish his species, are very different from true
spores by the thickness of their envelope, and by the nature
of their contents. Crushed under the microscope, they
permit drops of a very refracting liquid to escape, which
alcohol dissolves not, but of Avhich it renders the green
colour more brilliant. Sulphuric acid causes it to change to
a clear faAvn, and iodine to broAvn. I t is true that these
appendages are formed, like the spores, hy the condensation
of the green matter, and tha t they are separated from the
mother plant by a diaphragm ; but I have never found them
but upon filaments which have begun to disorganize themselves,
and almost always they decompose with them. Noav,
since I have constantly gathered in the same locality all the
individuals of Vaucheria Avhich have served for my observations,
and since I have seen them take successively all the
forms represented in the annexed plates, I believe tha t I
ought to unite Vaucheria ovata, clavata, sessilis, hamata,
terrestris, geminata, caspitosa, cruciata, into a single species,
Avhich I propose to designate under the name of Vaucheria
'Ungeri, in remembrance of the learned work of the German
author and his interesting discovery.
We have examined four different types of locomotive
organs in the spores of the A lg a : analogous organs are to
be found, without doubt, in a host of plants of this class; and
it is allowable for us to suppose tha t the different groups
present different forms. I should have been able myself to
add yet many genera to those which I have mentioned, but
I beheve th a t it would be sufficient in this first work to indicate
the principal types which observation has, up to the
present time, made me acquainted with, and to cite for each
of them a genus in which this type is found. I would add
in conclusion, in order to give more authority to my assertions,
tha t M. Deeaisne has verified the most part of my
results; and tha t I OAve him even certain of the figures Avhlch
accompany this note. (Ann. des Sciences Nat. 1843.)
c 3