373. BOTANICAL GAZETET [MAY 
accelerated growth, although a temporary inversion (one hour) is followed by 
diminished growth. In the case of the descending branches of weeping trees, 
gravitation not only causes a reduced rate of- growth, but also determines the 
locus of origin of new shoots. Growth correlations similar to those observed by 
RAcIBoRSKI in tropical lianas were obtained.—Raymonp H. Ponp. 
LAWRENCE? has published a bulletin containing a summary of our present 
knowledge and the results of his own investigations of a serious apple disease 
found thus far only in Oregon and Washington, that was first described by 
Corpiry*+ under the common name “apple tree anthracnose.” The disease is 
also known under the following common names: Oregon canker, black canker, 
blackspot apple canker, blackspot, deadspot, and sour sap disease. The present 
writer proposes that the disease be known as the “blackspot canker.” The 
fungus causing it was described by Corpiry?5 under the name Gloeosporium 
malicorticis, and has been described also by PECK?® under the name Macrophoma 
curvispora. This fungus is known to injure apple trees seriously in the Pacific 
northwest by the production of cankers upon the smaller twigs and branches. 
Similar cankers were produced by inoculation from apple cankers upon the 
cherry, plum, prune, and peach by Lawrence, and he is inclined to the belief 
that the same fungus is responsible for cankers upon all of the hosts named. As 
a rule cankers do not appear upon the larger branches and the trunk, owing 
apparently to the resistance offered by the corky outer layers of the bark of such 
regions to the penetration of the fungus. LAWRENCE here reports for the first 
time that the same fungus causes also a dry rot of stored apples that may be 
rather serious under certain conditions. The cankers may appear within a week 
from the time of infection; ordinarily appearing from November to February, 
rapidly completing their development after renewal of growth on the part of the 
ost, an oming mature by the next June or July. No definite statement can 
yet be made regarding either treatment of the disease or as to possible resistant 
varieties. —E. Mrap WILcox. 
A MUCH NEEDED INVESTIGATION of the réle of latex in the metabolism of 
plants has been commenced by Knrep,?7 and if continued may lead to valuable 
results. The paper here cited is presented in four sections. The introduction 
carefully reviews the literature, showing that theories are not supported by facts 
and that experimental results do not agree. The second section contains experl- 
23 LAWRENCE, W. H., Blackspot canker. Bull. Wash. Exp. Sta. 66. pp- 35- 
pls. 13. 1904. 
24 CORDLEY, A. B., Apple tree anthracnose: a new fungus disease. Bull. Oregon 
Exp. Sta. 60. pp. 3-8. pls. I-3. 1900. 
25 CORDLEY, A. B., Some observations on apple tree anthracnose. BOT. GAZETTE 
30: 48-58. figs. I-12. 1900. 
26 Peck, C. H., New species of fungus. Bull. Torr. Bot. Club 27:21- 1g00- 
27 Knrtep, Hans, Ueber die Bedeutung des Milchsafts der Pflanzen. Flora 
94:129-205. 1905. 
