the Spores of Varicellaria. 447 
a white corpuscle, which, towards the septum separating the 
cells, in most spores stretched out the sporal wall on one side. 
Thence I sometimes saw a white oblong corpuscle spon- 
taneously expelled from either cell. When free (or partly 
remaining within the cells and partly protruded near the sep- 
tum), these corpuscles became larger, and especially longer, 
than when enclosed within the spore, somewhat deformed, and 
unequal or almost cerebriform on the surface, but covered by 
no cellular membrane. 
Here, unless I am deceived, is the beginning of the thallus 
of the Lichen; but I have been unable to pursue the ulterior 
evolution. Does, then, fecundation take place in these corpus- 
cles? Their analogy would then be with the spores of the 
Fucacez. 
Subsequently, in the warm summer, I experimented with 
other cultivations of the spores of Varicellarta; and, as in the 
former ones, I beheld the mucedinous filaments speedily and 
copiously evolved from all. But now the fructification of 
Helminthosporium (spores septate, black, pyriform, moniliformi- 
proliferous, subfasciculate) appeared in these filaments, and the 
sporal wall became dissolved in a short time. Sometimes the 
corpuscles assumed a rose-colour. Too much heat (often 
about 30° C.) was injurious to this culture. 
Observations of this kind are very easily instituted and 
explained ; but in such experiments the natural conditions are 
so imperfectly imitated that consequently it is most difficult 
to attain to any knowledge of the physiology of Lichens. 
Corrigenda. 
In Dr. Nylander’s paper on “ Lichens in the Luxembourg Gar- 
dens” (Ann. & Mag. Nat. Hist. ser. 4. vol. ii. p. 245), I have inad- 
vertently made some gross mistakes, which need correction :— 
Page 246, line 5, for “‘ hygrometer” read hygiometer. 
Page 248, line 31, for “‘ Lecanora wmbrina = Lecidea pelidna, Ach.” 
read :—Lecidea umbrina is identical with Lecidea pelidna, Ach., 
which latter name is to be preferred for this lichen, because we 
have a Lecanora umbrina (Ehrh.) and because it is desirable to avoid 
a similarity of nomenclature in genera which approach so closely to 
each other. 
For “Heppe” read Hepp passim. W. A. Lerenton. 
