138 



GOOD FROM CROSSING. 



Chap. XVII. 



neously self-fertilised produced fruit, each containing on an avers 

 seed, whilst fruit from fourteen crossed flowers contained 24- 1 seed. 



(1866) 



5 



from Mr. Eobinson Munro. Three plants, including one in England, have 

 already been mentioned which were inveterately self-sterile, and Mr. Munro 

 informs me of several others which, after repeated trials during many 

 years, have been found in the same predicament. At some other places, 



wn 



Taymouth 



Donaldson on a distinct species, name unknown, and ever since the 



in 



this small and unnatural change in the state of this plant has restored its 

 self-fertility ! Some of the seedlings from the Taymouth Castle plant were 

 found to be not only sterile with their own pollen, but with each other's 

 pollen, and with the pollen of distinct species. Pollen from the Taymouth 

 plant failed to fertilise certain plants of the same species, but was successful 

 on one plant in the Edinburgh Botanic Gardens. Seedlings were raised from 

 this latter union, and some of their flowers were fertilised by Mr. Munro 

 with their own pollen ; but they were found to be as self-impotent as the 

 mother-plant had always proved, except when fertilised by the grafted 

 Taymouth plant, and except, as we shall see, when fertilised by her own 

 seedlings. For Mr. Munro fertilised eighteen flowers on the self-impotent 

 mother-plant with pollen from these her own self-impotent seedlings, and 

 obtained, remarkable as the fact is, eighteen fine capsules full of excellent 

 seed ! I have met with no case in regard to plants which shows so well 

 as this of P. alata, on what small and mysterious causes complete fertility 

 or complete sterility depends. 



The facts hitherto given relate to the much-lessened 



pletely destroyed fertility of pur 

 with their own pollen, in 



species 



wh 



comparison 



impregnated 



impregnated 

 fertility when 



: but 



by distinct individuals or distinct species 

 closely analogous facts have been observed with hybrids. 



Herbert states 73 that having in flower at the same time nine hybrid Hip- 

 peastrums, of complicated origin, descended from several species, he found 

 that "almost every flower touched with pollen from another cross produced 

 ' ' seed abundantly, and those which were touched with their own pollen 

 u either failed entirely, or formed slowly a pod of inferior size, with fewer 

 " seeds." In the ' Horticultural Journal ' he adds that, " the admission of 

 the pollen of another cross-bred Hippeastrum (however complicated the 

 cross) to any one flower of the number, is almost sure to check the fruc- 

 " tification of the others." In a letter written to me in 1839, Dr. Herbert 

 says that he had already tried these experiments during five consecutive 

 years, and he subsequently repeated them, with the same invariable result. 



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