1918] ALLARD—NICOTIANA 181 
disease. All phases of catacorolla have been noted. Very fre- 
quently the normal development of the corolla has been consider- 
ably exceeded, producing large and very showy blossoms, with a 
much folded and greatly increased circumference or border (fig. 5). 
Although the tobacco blossom is normally gamopetalous, the 
parts of the corolla may be more or less completely separated by 
clefts into petaloid segments. In some instances these have been 
replaced by very striking and beautiful ascidia or pitchers, borne 
Fic. 7—Abnormal blossoms of N. Tabacum produced by mosaic disease of tobacco; 
corolla development has been almost completely suppressed; in blossom at left pistil 
shows peculiar twisted structure; in blossoms at right, representing the 5 corolla lobes 
normally present, stamens and pistils are normal in development; hairy portion of 
filaments in normal blossoms is adnate to corolla tube.—T. 1508. 
upon long, slender, tubular stalks (see fifth blossom, top row, fig. 5, 
and third and fifth blossoms, top row, fig. 6). The blossom at the 
right in fig. 7 shows a complete separation of the corolla into 5 
distinct and nearly equal petaloid segments. In this blossom the 
normal development of the stamens and pistils has been but little, 
if at all, interfered with. Although nothing is known concerning 
the development of the various structures of the flower in con- 
nection with the mosaic disease, it appears that disturbances in 
the petal primordia are more likely to occur than in the primordia 
of other structures. 
