106 HYBRIDISING AND CROSS-BREEDING. 



ner was quite justified in declaring that the immediate influence 

 of foreign pollen upon the mother plant is a rare exception. 



" If we agree with Gaertner in excluding from the list, as 

 possibly due only to bud variation, those cases which are not 

 the result of direct experiment, the only well-established ones 

 which remain are those of Maize, * Peas, and Cattleya 

 Leopold^ 



In the ' Book of the Garden/ vol. ii. p. 321, Mr Anderson- 

 Henry records the interesting fact that he " once spoiled a 

 pure 7#/j//<?-bloomed Calceolaria for exhibition, by crossing it 

 with a crimson sort ; all the blooms on those branches where 

 the operation had been performed being stained red, and not 

 the few flowers merely which had been actually crossed." It 

 is undoubted that cross-fertilisation effects a change in the 

 embryo apart from mere fertilisation ; and the above facts go 

 to prove that changes effected by foreign pollen are not un- 

 frequently evident. 



Preservation of Pollen. The natural contrivances for the 

 due preservation of pollen are so varied and interesting, that 

 we must briefly allude to them ere entering on the more prac- 

 tical part of our subject. In the proceedings of the " Scientific 

 Society of Innsbruck," Dr A. Kerner has a valuable memoir 

 on different modifications of structure which flowers have 

 assumed, evidently for the purpose of protecting the pollen 

 from injury. Pollen is of two kinds, powdery and coherent. 

 The former kind is found almost exclusively in those plants 

 whose fertilisation is effected by the agency of the wind. The 

 quantity of pollen is in these cases enormous ; the anthers are 

 frequently attached very slightly to the end of elongated fila- 

 ments, so that the pollen is shaken out of them by the least 

 breath of wind ; the flowers grow on the most exposed parts of 

 the plants, frequently appearing before the leaves, so as to give 

 greater facility for the dispersion of the pollen, and are not 

 provided with brightly - coloured corolla, powerful scent, or 

 nectar, for the purpose of attracting insects. Plants, on the 

 other hand, whose pollen is coherent, are dependent on insect 

 agency for its dispersion and transport to the stigma. It is 

 therefore absolutely essential in these cases that some means 

 should be provided for its protection from moisture, whether 

 rain or dew, which would immediately destroy its efficacy, 

 until such time as it may be carried away by insects. A variety 



* See Trans. Royal Hort. Soc., vol. v. p. 234, for detailed account of 

 change of colour in the garden Pea by cross-fertilisation, with coloured plate. 

 In same vol., p. 63, is a most interesting paper on this subject, with refer- 

 ence to analogous cases. 



