OECHID CONFERENCE. 



411 



either with natural or false pollination they changed from white to 

 pale yellow in the original type, but in some c^i the best m.odern forms 

 the flowers assume a lilac shade. This seems to indicate that, although 

 now one so-called species, different characters have arisen during the 

 development of these newer forms. 



Mr. GuRNEY Wilson : Would Professor Keeble tell us whether it 

 is possible for more than one pollen grain to fertilize the same ovule ? 



Professor Keeble replied that so far as was known only one pollen 

 grain would have any effect on fertilization, although probably many 

 would grow down the substance of the style and possibly enter the ovary. 



Mr. H. G. Thwaites inquired what effect pollen grains from two 

 different species or hybrids placed upon the same stigma would 

 produce ? 



Professor Keeble said that either one or the other would probably 

 effect fertilization, for one would probably grow down the style more 

 rapidly than the other and reach the ovule first. 



Mr. E. A. Rolfe wished that some one would conduct a series of 

 experiments with Zygopetalum Mackayi in the same way that Sir 

 Harry Yeitch did with Cattleya Mossiae. It would then be possible 

 fco see whether the pollen tubes reached the ovules. He thought not, 

 for the seedlings were always pure Zygopetalums, and he believed they 

 were simply developed from parthogenetic buds as a result of the 

 stimulus of pollination. 



Mr. W. H. Hatcher : We have made an interesting cross at 

 Rawdon recently. The pollen of Odontoglossum crispum was placed 

 upon another flower of Odontoglossum crispum, and at the same time 

 pollen of Miltonia vexillaria was placed on the same stigma. The 

 result is curious, for every seedling shows very strong traces in its 

 habit of growth of the Miltonia. Although the seedhngs have not yet 

 flowered, it is clear the Odontoglossum pollen has had but little effect 

 upon the offspring, if any. 



In reply to questions Mr. Hatcher made it clear that the two 

 kinds of pollen were placed upon the stigma within a few minutes of 

 one another. 



Mr, J. M. Black asked whether any reason could be given for 

 some species of Orchids rejecting the pollen after it had been placed 

 upon the stigma. 



Mr. G. Wilson thought it was probably a matter of accommoda- 

 tion, for if the polhnium were too large it would be pushed off the 

 stigma by the closing over of the staminodes or side wings O'f the 

 column, which usually occurs after pollination. 



After some remarks by Mr. de Barri Craw shay, the Chairman 

 called upon Major Hurst for his paper on 



" THE APPLICATION OF GENETICS TO ORCHID 

 BREEDING." 



Major C. C. Hurst : The new science of Genetics has been built 

 up during the past decade on the firm foundations laid by Mendjol 



