R P. Gregory 87 



this year obtained a plant which possesses very deeply palmatifid 

 leaves. In addition to these variations, which affect the general aspect 

 of the leaf, there also occur less noticeable ones; as an illustration the 

 case may be cited of a plant, which occurred in an F„ family this year, 

 the leaves of which had serrate, instead of the usual crenate, margins. 



Palmate and Fern-leaf. 



The palmate character is iloiniuant, though a slight difference can 

 sometimes be recognized between the pure and heterozygous palmate 

 types. The shape of the leaf has been recorded in 27 F^ families raised 

 from crosses between palm- and fern-leaf, the numbers obtained being 

 1370 palmate, 457 fern-leaf (expectation : 1370-ii5 : 456-75). 



Ivy-leaf. 



In 1907 Mr A. W. Hill kindly gave me a monstrous plant (Plate 

 XXX, fig. 5) which occurred among a batch of seedlings raised by him 

 from seed obtained from a nurseryman. The leaves are palmate, but the 

 margins are not crenate, as they are in the ordinary form of leaf This 

 peculiarity of the leaves is always accompanied by abnormal develop- 

 ment of the flowers, which are very much reduced. The abnormality 

 is much more marked in the early flowers than in the later ones, and if 

 the plants be grown as biennials or perennials it is generally possible 

 to obtain good seed from such as survive. A seedling raised from the 

 original plant is shown in Plate XXXII, fig. 60. It will be seen that 

 the early leaves (the lower ones in the photograph) have more divided 

 edges than the later ones, and bear a closer resemblance to the leaves 

 of the ordinary palmate form. 



The absence of crenation of the leaf margin behaves as a recessive 

 character. The Fi from the cross with the ordinary palmate form is a 

 normal palmate plant. The F^'s raised from (F^ x self) have given 703 

 palmate, 241 Ivy (expectation : 708 : '336'0). Crossed with the ordi- 

 nary fern-leaf, the Ivy-leaf gives again a normal palmate plant (Plate 

 XXXII, fig. 61). This F„ selfed, gives an F^ (Plate XXXII, fig. 61, the 

 bottom row of plants) consisting of normal palmates, normal fern-leaves, 



' Bateson : "The progress of Genetics since the rediscovery of Mendel's papers," 

 Prog. Ret. Bot., Bd. 1, 1907, p. 373 ; Mendel's Principles of Heredity, Camb. Univ. 

 Press, 1909, p. 24. 



