Recent Works on Lichens. A. Lorrain Smith. 197 
meliaceae as Section 1: Parmelia, Sticta (comprising also Lobaria 
and Ricasolia) and Stictina, and as Section 2: Physcia, Ana- 
ptychia and Anzia. Why Anzia is placed along with Physcia he 
does not explain. 
Moreau (1921) also attacks the problem of classification ac- 
cording to thalline form in Stictaceae. He has examined the 
thallus of seven different species of Sticta, Stictina, Lobania, 
Lobarina and Ricasolia and would unite all these genera under 
Sticta. He finds in the development of the cephalodia a new 
proof of the phenomenon of biomorphogenesis, that is, in his 
view, the parasitism of the alga on the fungus, or a symbiosis 
that excites the fungus to unnatural growth. 
A curious morphological development is noted by Zahl- 
bruckner (1921); he records an upright branching Caloplaca 
from S.W. Africa: it had the outward form of Teloschistes, but 
without a cortical layer. Bouly de Lesdain (1921) describes a 
new genus of Pyrenolichens Henrica with rosulate thallus from 
which podetia-like structures are produced. The plant was 
found by Abbé Henry on schistose rocks in Italy. 
There have been published elaborate papers by Bachmann 
(1918 and 1922) which continue his work on endolithic lichens. 
He takes up calcicolous forms associated with Tventepohlia, 
Xanthocapsa and Scytonema (see also p. 194). Among the prin- 
cipal points in the paper, we note the description of an epinecral 
layer of dead hyphae and gonidia over the surface of the thallus 
of a number of species and above that layer in certain species 
a cap of slender living hyphae. He found also in the deeper 
layers of some species clumps of hyphae which he designates as 
“tubercles.”” There is great variation in respect of the position 
of the gonidial zone, but in most thalli solitary algal filaments 
penetrate more or less deeply into the rock unattached to 
hyphae. In other species similar filaments protrude from the 
surface of the thallus and live in the open. In most of the 
species associated with Tventepohlia oil-bearing hyphae or 
sphaeroid cells were present. 
Other forms of embedded lichens have been investigated by 
E. J. Fry (1922) in connection with the study of the pioneer 
cryptogamic vegetation of the limestones of Great Orme and 
S.E. Anglesea. She immersed chips of the rock in acid until the 
limestone was thoroughly dissolved; the thallus was then washed 
and prepared for microtome sections. She notes the differences 
in the cortical zone, the spacing of gonidia and hyphae, the 
character of the rhizoidal hyphae and above all the occurrence 
and form of oil cells (see p. 199). They were present in all the 
lichens examined (Verrucaria calciseda, Lecidea immersa, Pla- 
codium rupestre var. calvum f. incrustans, Aspicilia calcarea and 
