16 BULLETIN 879, U. S. DEPARTMENT OF AGRICULTURE. 
distinctly mottled, and the warty character is even more pronounced 
than on the cucumber. The symptoms differ from those on most 
cucurbits, however, in that the raised portions of the fruit are lighter 
in color than the surrounding surface. The contrast is often very 
pronounced, the warts being bright orange-yellow and the remainder 
a dark green (PL VI, B, O). 
The fruits of the Large Cheese pumpkin {Cucurbita moschata) show 
very marked mosaic symptoms, but these symptoms have not as yet 
been noted on any other variety of pumpkin susceptible to the disease. 
The young fruits are distinctly mottled with light yellow, and the 
surface is covered with large dark-green warts. (Pl.V, C.) At matur- 
ity the fruits are irregular in form, deeply furrowed, and the warty 
character is very pronounced. 
The fruits of most of the squashes, gourds, and the ornamental cu- 
curbits seem to be little affected by the disease, and on many of these 
hosts no symptoms have as yet been noted. The fruits of the mo- 
saic wild cucumber (Micrampelis lobata), however, are usually 
dwarfed, distorted in shape, and smoother than the fruits of normal 
plants, the spines being fewer in number and scattered unevenly over 
the surface. In a few cases fruits have been noted which devel- 
oped rather large irregular swellings. The epidermis of the fruit 
eventually splits open at these points and the tissues below push 
through to form dark-green swollen areas, which are somewhat 
similar to those found on the cucumber. (See PI. VII, D and F.) 
These symptoms apparently do not occur on all the mosaic fruits of 
this host, but they have been noted on a number of plants. The 
fruits of the 1-seeded bur cucumber (Sicyos angulatus), on the other 
hand, do not seem to show any evidence of the disease. 
BLOSSOM SYMPTOMS. 
Mosaic cucumber flowers are not streaked or variegated as are those 
of tobacco plants affected with mosaic. They are greatly reduced in 
number, however, especially the pistillate flowers. Blossoms pro- 
duced in the later stages of the disease are dwarfed, the corolla often 
measuring not over three-fourths of an inch in diameter, and are 
slightly paler than normal blossoms. On other cucurbits the symp- 
toms are of the same character, though the dwarfing is usually less 
pronounced except in the case of the muskmelon, the blossoms of 
which are usually reduced in size and number and are a much lighter 
yellow than those of normal plants. 
STEM SYMPTOMS. 
The stems in the case of the cucumber are shortened, as noted 
above (PI. II, A) , and where the older leaves have died the epidermis 
