508 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the presence of chlorophyll is very doubtful. A second kind of organ 
of propagation, resting sporanges, was also observed. BJiodocJiytrium is 
most nearly allied to Phyllobium, but differs in the presence of two 
kinds of sporange, in the mode of germination, and in the absence of 
chlorophyll ; in the last two characters it presents an approach to the 
Chytridiaceae. 
Tetrasporidium, a new Genus of Algae. * * * § — In a collection of Algae 
from Java, Prof. M. Moebius finds a freshwater species which he makes 
the type of a new genus allied to Tetraspora , and names Tetrasporidium 
javanicum. The following is the diagnosis of the genus : — Thallus 
spongiosus, irregulariter perforatus, structuram et multiplicationem 
cellularum eandem quam Tetraspora praebet ; reproductio fit sporis 
(zoosporis aut gametis ?) in cellula incrassata divisione succedanea 
senis denis evolutis, periplasmate multo in sporangio remanente ; 
diam. cellul. veg. 6-7 /x, sporangiorum 20-25 /x. The following new 
species are also described : — Cladophora Jiuviatilis , G. Beneckei , 
C. clavata , C. elegans , Siphonocladus exiguus. 
Fungi. 
Germination of Parasitic Fungi. | — M. M. Biisgen has studied the 
mode in which the germinating filament penetrates into the tissue of the 
host-plant in the cases of Botrytis cinerea , Fusicladium pyrinum , and 
several species of Peronosporeae, Erysipheae, and Uredineae. There is 
always the closest contact between the germinating parasite and the 
host, either by the apex only of the former, as in the Peronosporeae, or 
along its whole length, as in the Uredineae. The hyphae of the parasite 
which are in contact with the host put out swellings or “ appressoria,” 
by means of which this intimate contact is maintained, as well as by 
haustoria, or branches of the hyphae which penetrate into the tissue of 
the host-plant. These haustoria or “ infection-filaments ” are not the 
result of contact-irritation. The appressoria have the double function 
of causing intimate contact between the parasite and the host, and of 
indicating the direction in which the infection-filaments shall be put 
out. In the Peronosporeae and Uredineae this intimate contact is assisted 
by spontaneous nutations ; the movement of the zoospores of Cystopus 
towards the stomates appears to be partly the result of chemotropism. 
Botrytis cinerea also displays chemotropism as well as contact-irritation. 
New Parasitic Fungi. — The late Dr. C. Tubeuf J found Alnus viridis 
attacked by Valsa oxystoma, infesting the wood, and causing the leaves 
to fall. This fungus had previously been known only as a sapro- 
phyte. 
Prof. R. Hartig § finds a hitherto undescribed parasitic fungus, pro- 
bably a Nectria, attacking the seedlings of a number of trees, especially 
conifers, destroying them in the same way as Phytoplithora omnivora. 
It produces sickle-shaped usually six-celled conids ; and rudiments of 
peritheces or pycnids were observed. 
* Ber. Deutsch. Bot. Geselb, xi. (1893) pp. 118-39 (2 pis.). 
t Bot. Ztg., li. (1893) l te Abtheil., pp. 53-72 (1 pi.). 
% Forst-naturw. Zeitschr., i. (1892) pp. 387-90 (1 pi.). See Bot. Centralbl., liii. 
(1893) p. 329. 
§ Tom. cit., pp. 432-6 (4 figs.). See Bot. Centralbl., liii. (1893) p. 328. 
