204 BOTANICAL GAZETTE [APRIL 
fibro-vascular tissue thin in the normal scale. In the rudimentary leaves 
and summit of the stem there are neither resin-ducts nor mycelium during 
the winter. Resin ducts develop earlier in the season in the cortex of the 
twigs of the ‘‘broom’’ than in normal twigs, and they are always present 
in greater numbers in the former than in the latter. 
In the cortex of the “witch broom” tumor it occasionally happens that 
the communication by way of resin ducts between the diseased parts above 
the point of infection and the healthy parts below it is broken. Ducts are 
never formed in the phloem, while in the wood they are present in every 
annual ring. The diameter of these ducts and their number are greatest at 
the middle part of the tumor. From this point toward either end the diam- 
eter, number, and number of epithelial cells ineach, diminishes. At the lower 
end all the ducts are pointed and terminate between diseased and normal 
wood. In the upper extremity all ducts which end with the tumor are pointed. 
Ducts seem to occur as often in the wood of healthy twigs having their origin 
above the point of infection as in that of the diseased ones. In the wood of the 
tumor there is usually, in each annual ring, a circle of ducts and sometimes 
two such circles. , 
Tissues of Picea excelsa, Pinus Strobus, and Larix Japonica infected with 
Agaricus melleus show that there is an increase in the number of vertical 
ducts in the diseased wood ring in all parts of the plant above the point of 
infection. Yhe greatest increment of wood in the diseased ring is found in 
the upper part of the plant, from which downward the thickness of the ring 
* decreases. With this decrease in thickness there is a corresponding increase 
in the number of resin ducts per square unit of section surface. In Adzes 
pectinata infected with Phoma abietina resin ducts occur only in the healthy 
wood above the diseased part of the branch. These ducts are similar to those 
in the wood of the “witch broom” on Abies. Tissues of A dies pectinata and 
awe excelsa infected with Pestalozzia Hartigti show in the former the forma- 
abnormal ducts only in the sound wood above the diseased part of the 
stem and in the latter the formation of a larger number of ducts in the healthy | 
| wood above the diseased part of the stem than is found in normal spruce 
. wood.—L. s. CHENEY. 
tng Hi the plant and animal into a system ha aiisera terminology. 
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