570 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
tlic cells which it attacks. It consists of a single cell surrounded by a 
membrane. Its systematic position was not determined. 
Stromatopogon, a Hew Genus of Lichens.* * * § — From the Sandwich 
Islands, Herr A. Zalilbruckner finds a lichen which he makes the type 
of a new genus, with the name Stromatopogon Baldwini g. et sp. n., 
growing on the trunks of trees. It resembles TJsnea, but belongs to the 
Coniocarpei with a strongly developed thallode, but greatly reduced 
fructification. The author regards the genus as the representative of a 
new type of the Sphaerophorei. 
Reticulations of Ramalina reticulata.f — Mr. G. J. Peirce has 
investigated the cause of the perforations which produce the netted 
appearance in all thalli, whether old or young, in this lichen, probably 
the largest known in size. They are not produced simply by the un- 
equal expansion in three directions, although this is the main factor in 
the older parts ; it is also the curving and consequent straining longi- 
tudinally of the softest and least coherent portions of the thallus, near 
the tip, by the folding over of the apex, and the concentration, owing 
to the narrowness and circinate curving of the apex, of the greatest 
transverse strain in that zone where the longitudinal strain is also 
greatest. The ordinary mode of propagation of the lichen is a vegeta- 
tive one, the rain softening the thallus, and causing the detachment 
of large pieces which are carried to a great distance by the wind. 
Hew Text-book of Lichenology.J— Dr. A. Schneider’s new Text- 
book of Lichenology is intended primarily for the use of students in 
colleges and universities. It is divided into two parts, the first treating 
of the history, general morphology, and physiology of lichens ; the 
second, of their classification and special morphology. The phenomena 
of symbiosis are classified under antagonistic symbiosis (parasitism), 
nutricism, and mutualistic symbiosis. Five families of Fungi are given 
as probable ancestral groups of fungal symbionts ; and nine genera of 
algae are named, which are known to enter into symbiotic relationship 
to form lichens. The structure of the thallus and apothece is adequately 
described. 
The author proposes a system of classification of lichens, founded 
on their fungal ancestry, the primary division being into the three 
orders, Ascolichens, Basidiolichens, and Gasterolicliens, based on the 
method of spore formation of the fungal element. As generic characters, 
those of the spore are given as of primary importance, then the develop- 
ment of the thallus, the apothece, the exciple, the colour of the apothecial 
disk, and the colour of the thallus. A number of genera are based 
upon algal differences. Seventy-seven genera of Lichens are recognised. 
Cytological Researches on the Yeast-Cell.§ — The results of a care- 
ful examination into the cytological characters of the yeast-cell by Prof. 
F. A. Janssens and M. A. Leblanc are summed up as follows. In the 
quiescent condition every yeast-cell contains a nucleus, which is made up 
* Arm. k. k. Naturh. Hofmuseums, xii. pp. 99-102 (2 pis.). See Hedwigia 
xxxvii. (1898) Eep., p. 72. f Bot. Gazette, xxv. (1898) pp. 404-16 (8 figs.). 
X Schneider, A., ‘ A Text-book of General Lichenology,’ Binghampton, N.Y., 
230 pp. and 6 pis. See Bot. Gazette, xxv. (1898) p. 284. 
§ La Cellule, xiv. (1898) pp. 203-41 (2 pis. and 67 figs.). 
