LICHENS UNDER THE MICROSCOPE. 669 
distinguished from fungi. There are some parasitic plants, 
consisting only of apothecia, which grow on the thallus of 
other lichens, called by Massalongo and Koerber, Pseudo- 
lichens, which are considered by some as 
lichens, by others as fungi. Most of them 
give the characteristic blue reaction with 
iodine. In examining a section of a young 
specimen of one of these, Scutula Wall- 
rothii Tul. (Biatora Heerii Hepp), which 
grows on the thallus of Peltigera canina, I have seen a 
stratum of true gonidia un- 
derlying the apothecia, and 
extending around it. Some 
of these parasites are doubt- 
less lichens, while others 
must be relegated to the 
ascomycetous fungi. 
Section of apothecium of Theloschistes parie- The gonidia are either of X 
toja, greenish yellow color, as men- 
tioned above, as in Physcia, Parmelia, and the greater number 
of lichens; or of a bluish green, as in Collema, Peltigera, 
some Stictas, ete. These latter are called granula gonima, 
or collegonidia. In Collema Fig. 145. 
they are strung together like a 
chaplet of beads, and are called 
moniliform (Fig. 140, 6). In 
some genera they spring from 
the end of thalline filaments, 
in others they are grouped 
together, enveloped in a trans- 
Fig. 143. 
Granula gonima of 
Sticta fuliginosa, 
Fig. 144. 
Portion of same more enlarged; ch, 
3 pe rape i 
parent gelatinous substance, and ae wa; jum vomer: f 
" y layer. 
araphyses 
surrounded by a thin membrane kondia; mi — 
(Fig. 143). In Synalissa both kinds of gonidia occur. 
They frequently burst into mealy excrescences, cà ed s0- 
redia, on the surface of the thallus, and have the faculty of 
mültiplying by self-division and of propagating the plant, 
