72 



ItOYAL llOUTICULTimAL SOCIETi'. 



but it is of course more difficult to indicate the points of resem- 

 blance and difference. 



Grsertner indeed supposes that in genera which are rich in 

 species, there are some which have a prepotent influence when 

 hybridiziug, so that in some hybrids the type either of the male 

 or female parent prevails. Amongst the various hybrid willows, 

 though the genus is so rich in species and so prone to hybridizing, 

 "Wichura has never seen a prepotent type, and doubts Glsertner's 

 statement, especially as he makes it in very qualified terms. 

 With respect to the critical examination of types — whether, for 

 example, a hybrid is more like the mother or father — the perfect 

 distinction is subject in many cases to great difficulties, since very 

 much depends on the subjective view of the observation ; for in 

 consequence of the frequent intermelting of both characters, the 

 one observer finds in a hybrid the maternal type, while another 

 thinks the paternal type prevalent. 



The question is of more importance whether the paternal or 

 the maternal parent has most influence on the form of the hybrid. 

 GrSBrtner has made many experiments in this direction, and says, 

 " The most important and interesting phenomenon in the inter- 

 crossing of plants is the perfect equality of either production ; 

 seeds arising from the impregnation of either parent produce 

 plants of the most complete resemblance ; so that the different 

 origin, on the most careful examination of either kind of hybrid 

 in respect of formation and type, does not induce the slightest 

 difference." Slight differences were said to occur in the genus 

 Digitalis only, but it is doubtful whether these depend on inter- 

 crossing or on some other conditions. JS. ( $ caprea-{- S viminalis) 

 and S.( $ viminalis + 6 caprea) did not present the slightest differ- 

 ence in the number of normal pollen-grains or in their outer form, 

 but their resemblance was so perfect that they might be taken 

 for products of one and the same crossing. 



Since the variable characters of species maintain their pecu- 

 liarity as such in their progeny, a wide margin is left for the for- 

 mation of varieties in hybrids which comprise the variable charac- 

 ters of two species, notwithstanding the law of intermediation. 

 The most remarkable examples are afforded by those hybrids 

 which exhibit the prevailing characters in different parts of the 

 same individual. The occurrence of such types is placed beyond 

 doubt by such productions as Cytisus Adami, a hybrid of C. Labur- 

 num smdpurpureus*. Mixed types are, however, very rare, and 

 nothing of the kind has ever occurred amongst willows. 



* It is very doubtful, however, whether this be a hybrid at all. It is believed 



