218 Ciftology and Genetics of the Genus Fuchsia 



(15, p. 108) has pointed out with justice that such an unequal partition 

 of the chromatin need not necessarily lead to the sterility of the resulting 

 pollen grains. At the same time one cannot avoid the conclusion that 

 the fact of the existence of such an abnormal distribution is an earlj- 

 indication of a derangement in the mechanism of the cell and, in the 

 Fuchsias at least, this may become intensified in the later stages of 

 development so that many of tlie pollen grains which result become 

 sterile. This sterility of the pollen grains has frequently (see 2) been 

 regarded as the peculiar attribute of hybrids, but the list of Fuchsias 

 which has been given above does not support this view. 



Thus F. arhoresceris, which is a pure species, produces a large pro- 

 portion of sterile pollen, whilst a definite cross between F. ptimila x 

 F. alpestris exhibits quite regular pollen development, and nearly all 

 the grains which are pi-oduced are fertile. Other instances of the same 

 fact will be seen in the list. 



A study of the species and varieties of Fuchsia shows quite definitely 

 that the hybrid character is not the only determining factor in the pro- 

 duction of sterile pollen grains. 



There are a number of other instances already known in the literature 

 which all point in the same direction. Thus Gates and Goodspeed(7) 

 have recently described a number of interesting cases of pollen sterilit}^ 

 in plants which are undoubtedly not hydrids. A striking instance of 

 this is to be found in Scoliopus Bigelovii in which, with all possibility of 

 crossing excluded and in their native habitat, from 3 per cent, to 32 per 

 cent, bad pollen is produced, whilst in individual anthers the observed 

 amount of bad pollen exceeded 45 per cent. "This in itself is a sufficient 

 refutation of the hypothesis that bad pollen is necessarily a sign of 

 hybridity." "Pollen sterility is rather a physiological condition which 

 occurs in all degrees of intensity and may be duo to a variety of causes" 

 (7, pp. 3 and 4). 



Dorsey(4) has also concluded that in the grapes hybridity is not 

 necessarily the cause of sterility since both sterile and fertile hybrids 

 occur among cultivated varieties. 



Earlier references pointing to the same conclusion may be found 

 in the literature. Thus Lidforss (9 and 10) found that the hybrid 

 Rnbus caesiiis ^ x Rubus acmninatus $ had a higher percentage of good 

 pollen than one of its parents (R. acmnivatus). Hildebrand(8) recorded 

 the fact that whilst the hybrid Chaniaedorea Ernesti Augasti $ x Ch. 

 Scliiedeana ^ produced mostly bad pollen, the reciprocal cross gave rise 

 to individuals in which the pollen appeared normal. 



