1897 | “ BACTERIOSIS” OF CARNATIONS 201 
or in the leaves of the false indigo (Amorpha fruticosa), anative shrub, except 
that they have no regular disposition. Sometimes the surface of the leaf is 
slightly raised over the dots, making watery pimples. 
fter a time the surface of the leaf above the dots changes enough to 
indicate their presence, and finally shows a distinct spot. As the disease 
extends inside the leaf the surface tissues collapse and whitish sunken spots 
appear. In some colored varieties of carnation the spots vary somewhat by 
being more or less reddish or purplish. As the spots increase in size the leaves 
wither, still clinging to the stem, Such spots never show distinct darker 
colored specks and rarely any concentric circles, as do the spots made by 
parasitic fungi, such as Septoria (spot disease) and Heterosporium (fairy 
ring), 
Very badly diseased plants, especially when much crowded and growing 
in damp atmosphere, have more yellowish green leaves than normal, of a 
more transparent appearance, and usually smaller. The lower leaves of dis- 
eased plants in any atmosphere or soil die prematurely and the vitality of the 
plant is so lowered as to check the growth and “decrease the size and number 
of the flowers. 
Arthur and Bolley find that ‘no varieties of the carnation 
are exempt from the disease, but they differ much in suscepti- 
bility. The seat of this difference is chiefly in the vigor of the 
plant. . . . . Poorly grown plants are more affected than those 
well grown. Partly starved or stunted plants are specially liable 
to attack.’’ They found the disease at Indianapolis, La Fayette, 
and many other places in Indiana, and in Buffalo, Boston, New 
York, Toronto, Chicago, and Lincoln. They say it is common 
throughout eastern North America wherever carnations are 
grown extensively, and conclude that it is caused by “ parasitic 
bacteria entering the plant from the air through the stomata, or 
occasionally through the punctures of aphides.”® 
The disease which has: formed the subject of our studies 
agrees in all essential points with the one just described, except 
that it is not caused by bacteria. Our material was obtained 
from many of the large centers of carnation growing in the 
United States, and through the kindness of Dr. Arthur good 
Specimens were recently sent in from Mr. Fred Dorner’s place 
at La Fayette, Ind. 
SARTHUR and BOLLEY, loc. cit. 32 and 37. 
