312 



GENETICS IN RELATION TO AGRICULTURE 



examples of like improvement. Unquestionably the amateur plant 

 breeder can find no more fascinating or productive line of activity than 

 that of selecting and working with some particular group of species from 

 this standpoint. 



Origin of Varieties in the Boston Fern. In 1915 Benedict reported 

 that he had accumulated about 40 different forms of the Boston Fern, 

 all of which had originated so far as is known from bud sports. The 

 following statements regarding the source of these new varieties are 

 based on Benedict's account. The original Boston Fern arose as a bud 

 mutation from the tropical species, Nephrolepis exaltata. It was first 



Fio. 128. 1. The original Boston fern, Nephrolepsis exaltata bostoniensis; 2, the first 

 bud sport from the Boston, N. exaltata bostoniensis Piersoni; 3, the Pierson fern next pro- 

 duced elegantissima; 4, N. compacta, a sport from elegantissima. (Courtesy Brooklyn Botanic 

 Garden.) 



recognized as different from exaltata by F. C. Becker of Boston, and 

 in 1896 it was named N. exaltata var. bostoniensis. The typical form of 

 the species and the first sport, bostoniensis, are large growing ferns with 

 uni-pinnate leaves (Fig. 128, 1). In the remarkable series of bud muta- 

 tions that have been derived from bostoniensis within two decades, the 

 principal characters undergoing transformation are, first, form of pinna 

 and hence form of frond ; second, size of frond ; third, form of frond con- 

 sidered independently of pinna-form ; fourth, color of foliage. 



The original sport from the Boston fern was bi-pinnate; i.e., each 

 pinna was subdivided into little pinnae or pinnules (Fig. 128, 2). This 

 form appeared about 1900 in the establishment of F. R. Pierson of 

 Tarrytown on the Hudson, and was named Piersoni or Tarrytown fern. 

 It did not produce satisfactory plants because only part of the fronds were 

 bi-pinnate; the remainder resembled the original Boston variety. 



