Fasciation in the Sweet Potato. 



(WITH PLATE XIX.) 



By Henry S. Conard, A. M. 



The occurrence of fasciation or broadening of normally 

 round plant axes has been often noted in a great variety of 

 plants. Ferns, lycopods (9), gymnosperms, monocotyls and 

 dicotyls alike show it, in frequency according to the order 

 of mention ; it is most commonly observed in dicotyls. In 

 shrubs, trees and herbs, following the increasing order, it has 

 been recorded. The condition is most common in vegetative 

 and flowering stems, being very rarely found in roots (i, 2),7). 

 It appears most in plants subjected to conditions of nourish- 

 ment above the normal (4), occasionally, perhaps, as a result 

 of disease (13) or injury (2, 8, 16). Frequently many of the 

 plants in a certain locality will be fasciatcd, e. g., ^. field near 

 Hainesport, N. J., which yielded in the summer of 1899 

 dozens or even hundreds of fasciations of Riidbcckia hirta 

 L. (11); also a meadow near Haddonfield, N. J., where 

 Rammcubis bidbostis L. was quite as largely fasciated in 1893 

 (10) ; at Cape May, N. J., Desmodiiim ciliare DC. was fre- 

 quently found fasciated by Professor Macfarlane in 1 899 ; and, 

 finally, at Fallsington, Pa,, the writer observed fasciation in a 

 species of Lactuca in 1899 and 1900. Such localities have 

 been noticed to produce fasciations year after year. This fact, 

 and the occurrence of so many individuals in so narrow a 

 space, may result from the hereditaiy nature of this condition, 

 as shown in Celosia cristata of gardens, and in de Vries' 

 fasciated races. The Clyde strawberry bears fasciated flower- 

 stalks, and hence, fasciated berries of huge size. 



The common sweet potato (^Ipomcca Batatas Poir.) as grown 

 about Philadelphia produces fasciated vines very plentifully, 



(205) 



