188 SALMON: SUPPLEMENTARY 
where the tips of the germ-tubes had come into contact with the 
cover-glass (see f/. 9, f. 9). No formation of haustoria pro- 
ceeding from these was observed. This phenomenon was first 
noticed by Bisgen (11), who remarks of the germinal hyphae 
proceeding from conidia of £. polygoni sown in the same way : “ bei 
Beruhrung mit dem Objecttrager erzeugten sie lappige Appres- 
sorien, mit deren Bildung ihr Wachsthum abgeschlossen war. 
Ein Austreiben der Appressorien fand nicht statt, obwohl der 
Inhalt der Gonidien noch nicht erschdpft schien. Es darf daraus 
geschlossen werden, dass auch bei den Erysipheen zur Entwicke- 
lung des Infectionsfadens ein Ernahrungsreiz nothwendigist, der 
in der Natur nur von der Wirthspflanze ausgehen kann.” 
In the Journal of the Royal Horticultural Society (London) 
for 1900 (35) it is reported that the prevalence in autumn, in some 
parts of Britain, of the “ pea-mildew” (Z. polygoni), is causing the 
cultivation of late varieties of peas to be abandoned. A similar 
state of affairs has already been recorded in the western United 
States by Bessey (Seventh Biennial Report Iowa Agric. Coll., 
1877). Dusting the infected plants over with flowers of sulphur 
(mixed with air-slacked lime), or spraying with a solution made by 
dissolving 3 oz. of carbonate of copper in 2 quarts of aqua am- 
monia diluted to 22 gallons, is stated to be the best means of com- 
bating the disease. (See Galloway, on the “ Powdery Mildew 
of the Bean,’ Journ. Myc. 5: 214. 1889.) Lodeman (40%, Pp. 
325) writes of the “Pea Mildew”: “This disease could un- 
-doubtedly be easily checked by means of the copper sprays, but 
the foliage of these plants is of such a character that liquids do not 
readily adhere. Soap will assist in overcoming this difficulty if it 
is added to the liquids. Another line of treatment which might be 
followed by good results is to apply powder to the vines while 
they are wet with dew. Fostite should prove of value for this 
purpose.” 
In 1891 Comes (13*) described under the name Ozdium cera 
toniae a mildew which had been observed for several years Pre 
viously on the carob-tree (Ceratonia Si/iqgua) in southern Italy. 
This fungus is stated to attack by preference the younger leaflets, 
which become deformed and fall off, the young shoots, and the 
immature fruits. When the mildew appears at the time of flower- 
