44 Transactions British Mycological Socvety. 
living in a free state. The photomicrograph, fig. 5, is very like 
that of the drawings by Grintzesco, which illustrate the paper 
on Chlorella vulgaris, with the exception that the chloroplast of 
the daughter cell in the drawings is decidedly clear at one 
spot (6). It is not so in the illustration in West, p. 194 (12). The 
latter adds in his description of the division of the free Chlorella 
cell ‘‘It is almost exactly like the formation of zoogonidia in 
so many of the Protococcales and it is not unlikely that the 
daughter cells are reduced zoogonidia.”” The same may be 
said of the formation of daughter gonidia within the lichen 
thallus. 
Diagrams and drawings hitherto published for the purpose of 
illustrating a transverse section of a lichen thallus containing 
bright green gonidia convey the idea that the cells are at all 
periods approximately of the same size even when they are 
described as cells of Protococcus which divide vegetatively by 
the formation of a transverse wall along which segmentation 
takes place. The actual separation of the two daughter gonidia 
is not indicated. There are very few published drawings that 
suggest sporulation, and when such a suggestion does appear, 
as in two of the illustrations by Schwendener (9) no description 
of this condition of the cell is given. The statement is made 
that the cells are dividing and this has been interpreted as 
meaning in all cases, dividing vegetatively. The partition wall 
(eine zarte Scheidewand) is specially referred to. De Bary, 1884, 
16 years after the publication of Schwendener’s classical paper (8) 
says “‘The Fungus alone produces spores, the Alga with a few 
exceptions remains barren as long as it is combined with the 
Fungus.’ The only exception that de Bary notes is that of 
Synalissa symphorea, a lichen with a blue-green alga(r). This 
form of gonidium is not under discussion in the present paper. 
The algae Cystococcus and Protococcus are described as the 
gonidia of lichens, the first by Schwendener (8) and the second 
by Bornet (2), but great uncertainty concerning the identity of 
these has arisen from the fact that in neither case is a detailed 
account given of the gonidium. The transverse partition 
of the gonidium, shown in a few of Schwendener’s drawings, 
does resemble a vegetative division, and was regarded as such 
by the author(z0), but in the light of our present knowledge 
the so-called transverse walls may be the first indication of the 
splitting up of the protoplast that occurs at the commencement 
of sporulation. In Pl. VIII, fig. 10 of Schwendener’s paper (9) 
there is a gonidium showing three internal masses out of four 
that are present; they are similar in shape and arrangement to 
those now shown in the sporulating gonidium of E. prunastri, 
fig. 3. In both cases three of the tetrahedrally arranged masses 
