IZ, Miscellaneous. 
a specimen of Argiope fasccata, which is thus located upon the 
Pacific coast, giving this beautiful and interesting spider a conti- 
nental distribution.—Proc. Acad, Nat. Sci. Philad. 1883, Noy. 27, 
p. 276. 
On an Aerial Alga inhabiting the Bark of the Vine. 
By M. J. B. Scunerztzr. 
In the month of April of the present year (1883) there was 
observed upon numerous vines between Pully and Belmont (Canton 
de Vaud) a pulverulent matter of a brownish-red colour, which 
penetrated into the fissures of the periderm. This pulverulent 
matter is formed by an aerial alga, Chroolepus umbrinum, Ktz., or 
Trentepohlia umbrina (Kg.), Born., which is met with upon the 
bark of various trees, but has not hitherto been mentioned upon that 
of the vine. This alga contains a very refractive red oil, which 
diffuses a faint odour of violets; it does not appear to injure the 
vine, upon which occurs a complete cryptogamic vegetation formed 
by species of Oscillaria, Nostoc, and Pleurococcus, Confervee, Mosses, 
and Lichens (Physcia ciliaris, Pyrenula, &c.). Chroolepus umbrinum 
is composed of small spherical cells of about 30 y, forming small 
curved chains. 
When the bark of the vine reddened by Chroolepus umbrinum is 
moistened with water, this same alga is seen very distinctly in the 
thallus of one of the lichens of the genus Pyrenula. It must be re- 
marked, however, that the cells of the alga which occur in the 
thallus are smaller than those which exist in the air; they form in 
it very distinct little chains. We observe, moreover, all the transi- 
tions between the cells which exist out of the thallus and those which 
occur more or less deeply buried in it. Around the chaplets and 
free cells of the Chroolepus we sometimes find the filaments of the 
mycelium of a fungus, which surround them and bind them into 
small colonies. 
The cells of Chroolepus umbrinum, which occur either in the free 
state or immersed in the thallus of Pyrenula, often present a green 
coloration. One can find all the transitions between entirely red 
cells and others partially or entirely green. This green coloration 
is met with especially when vine-bark reddened by the free Chroo- 
lepus is plunged into water. In this latter case we see issuing from 
some of these cells, which are still red, small ovoid bodies which 
swim briskly in the water (zoogonidia of Wille *), 
In avery interesting memoir by M. A. B. Frank f we find some 
observations precisely analogous to the preceding. It results from 
them, as we have likewise ascertained, that Chroolepus umbrinum 
may lead a completely free and independent existence, while the 
same alga occurs with smaller dimensions in the thallus of crusta- 
ceous lichens ; but when, in consequence of the disaggregation of this 
thallus, the alga is set free, it multiplies and by degrees resumes 
its typical form and its normal dimensions.—Bulletin de la Société 
Vaudoise des Sciences Naturelles, sér. 2, vol. xix. no. 89, p. 53. 
* Just, Bot. Jahresber. 1878, p. 390. 
+ “Ueber die biologischen Verhaltnisse des Thallus einiger Krusten- 
flechten,” in Just, Bot. Jahresber. 1876, p.70. 
