834 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
and at the station for diseases of plants at Rome, proceeds to discuss 
certain fungi. 
(1) MoniVa cinerea Bon. is found as a parasite on the flower stems of 
pears, and kills the flower-buds. 
(2) Didymaria prunicola sp. n. This new parasite grows on plum- 
leaves, which are covered with numerous round dry spots. On micro- 
scopical examination numerous fungus filaments are seen between the 
cells of the tissue of the leaves, aud penetrating within by means of 
short ramifications. Separate hyphse grow out from the under side of 
the leaf, and produce conidiophores, which form simple two-celled 
unbranched filaments with a two-celled elliptical or egg-shaped spore at 
the apex. The spores measure 12-17 /jl in leugth and 5-9 /x in breadth, 
the length of the conidiophore being 120-220 /x and its breadth 2 5-3 
/x. The pathogenic character of the fungus was not proved experimen- 
tally. The author recommends sulphur as a remedy. 
(3) Cladosporium condylonema Pass, also produces a spotty disease of 
plum-leaves and damages the tree by causing the leaves to fall otf too 
soon. Collection and destruction of the fallen leaves, as well as the use 
of sulphur, and sprinkling with sulphate of copper are recommended by 
the author. 
(4) Septoria effusa Desm. This rare fungus causes the leaves of the 
sweet cherry to wither. 
Verrucaria consequens.* — M. C. Bommer describes in detail the 
structure of this marine lichen, found on shells of B alarms, and believes 
it to be the result of the symbiosis of an alga, Hyella csespitosa , with 
two distinct fungi, Bornet’s Ostracoblabe implexa and a species of 
Pharcidia , belonging to the Pyrenomycetes, of which the peritheces 
and asci were detected. The author appends a list of marine lichens 
at present known which are entirely submerged, viz. Verrucaria maura, 
V. antricola , V. microspora , V. littoralis vars. consequens and lialodytes , 
V. leptotera var. marmorans , and Lichina pygmsea ; and of others which 
are partially submerged, viz. Lecanora prosechoides, L. murorum , L. 
marina, Aspicilia gibbosa, Lecidea alboatra var. glaucoatra , Verrucaria 
scotina, V. marinula, and Licliina conjinis. 
Sulphuretted-hydrogen-forming Yeast.f — M. Crouzel describes a 
yeast, forming sulphuretted hydrogen, which thrives only in acid or 
neutral solutions, dying in alkaline. A useful medium is urine after 
the ammoniacal fermentation has ceased, and to which sulphuric acid 
in quantity just sufficient for neutralization has been added. Sulphu- 
retted hydrogen and allied compounds are produced by this yeast. 
Access of air must however be prevented, otherwise the fermentation 
products are reduced to sulphates, apparently through the agency of 
mould fungi which spread themselves over the surface of the cultivation. 
To cold, high temperatures, and drying the yeast is extremely sensi- 
tive, and is easily killed thereby. In sugar solution it produces only 
a little alcohol, but no inconsiderable quantity of lactic acid. 
* Arm. Soc. Beige Microscopie, xvi. (1892) pp. 79-99 (1 pi.). Cf. this Journal, 
ante, p. 242. 
t L’Union Pharmaceutique, xxxiii. (1892) p. 60. See Ceutralbl. f. Bakteriol. u. 
Parasitenk., xi. (1892) pp. 800-1. 
