Q OBSERVATIONS UPON MULING AMONG PLANTS. 



It was said above that hybrids may be divided into interme- 

 diate, mixed, and decided types. These divisions, however, are 

 far from being- strictly definite. Each of these heads may be 

 briefly considered. 



First, then, hybrids occur in which the characters of the 

 parents are so intimately blended, that it is impossible to say to 

 which there is a greater resemblance. Something in such cases 

 must depend upon individual judgment, and the degree of apti- 

 tude in tracing accurately differences and points of resemblance. 

 Sometimes the result as to the number of organs, where differ- 

 ences exist in the parents in this respect, is curiously interme- 

 diate : as, for instance, from the three stigmas of Cucuhulus and 

 five of Lychnis, arise the four of Lycnicticubalus, 



The second class is tliat of mixed liybrids. In these, one part 

 or other of tlie hybrid approaches the paternal or maternal form, 

 though the characters of the parents never pass altogether pure 

 into the new organism. Melons are a familiar instance ; or, to 

 take one more special, in Lychnis vespertino-diurna there is no 

 perfect diurnal sleep, as in L. vespertina, but the petals roll back 

 slightly when the sun shines, or the weather is hot. The hybrid 

 resembles L. vespertina in its smaller leaves, diuma in the 

 vital phenomena — vespertina in the larger flowers and straight 

 blunt stigmas, diurna in the pubescence — vespertina in the more 

 pyramidal fruit, as also in tlie size and colour of the seeds. 



Thirdly, we have the decided hybrids — viz. those in which the 

 resemblance to one of the parents, whether male or female, is so 

 decided, that the agreement is at once perceptible and beyond 

 all doubt. It might be supposed that in this case the predomi- 

 nance of one of the parents might prevent alternate crossing, it 

 being scarcely probable that when the parents were reversed, 

 the result under such circumstances could remain the same. In 

 some instances, indeed, of decided hybrids, alternate crossing 

 does not succeed ; but this is far from constant, and in some 

 most decided types the parents may be successfully reversed. 

 Lobelia cardinali-syphilitica is a case in point. There are some 

 species, producing decided hybrids, which, when united with 

 several others successively, always predominate in the resultant 

 types. These species have usually some strong peculiarity about 

 them, but it cannot be asserted a priori what species are likely 

 to exercise such an infiuence, and there are other species, again, 

 which prevail even over these. For instance, Dianthus har- 

 hatus, which communicates its type, as regards leaves and general 

 habit, to JJ. Anneria, prolifer, and Carthusianortim , is in its 

 turn overcome by L>. caryopJiyUus and superhiis. These spe- 

 cies have been called, but not very happily, generic types. 

 These predominating types show clearly that the ratios of the 

 potency through which the union of two pure species takes 



