HYBRIDISM 13 



shown by Professor Hildebrand, in various orchids as 

 shown by Mr. Scott and Fritz Miiller, all the individuals 

 are in this peculiar condition. So that, with some spe 

 cies, certain abnormal individuals, and in other species 

 all the individuals, can actually be hybridized much more 

 readily than they can be fertilized by pollen from the 

 same individual plant! To give one instance, a bulb of 

 Hippeastrum aulicum produced four flowers; three were 

 fertilized by Herbert with their own pollen, and the 

 fourth was subsequently fertilized by the pollen of a 

 compound hybrid descended from three distinct species: 

 the result was that "the ovaries of the first three flowers 

 soon ceased to grow, and after a few days perished en- 

 tirely, whereas the pod impregnated by the pollen of the 

 hybrid made vigorous growth and rapid progress to ma- 

 turity, and bore good seed, which vegetated freely." 

 Mr. Herbert tried similar experiments during many 

 years, and always with the same result. These cases 

 serve to show on what slight and mysterious causes the 

 lesser or greater fertility of a species sometimes depends. 

 The practical experiments of horticulturists, though 

 not made with scientific precision, deserve some notice. 

 It is notorious in how complicated a manner the species 

 of Pelargonium, Fuchsia, Calceolaria, Petunia, Rhododen- 

 dron, etc., have been crossed, yet many of these hybrids 

 seed freely. For instance, Herbert asserts that a hybrid 

 from Calceolaria integrifolia and plantaginea, species most 

 widely dissimilar in general habit, "reproduces itself as 

 perfectly as if it had been a natural species from the 

 mountains of Chile." I have taken some pains to ascer- 

 tain the degree of fertility of some of the complex 

 crosses of Rhododendrons, and I am assured that many 



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