32 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



plant species and believe in a continuous evolution of vegetation. He 

 perceives in the complete transformation of one species into another an 

 indubitable proof that species are fixed within limits beyond which they 

 cannot change. Although this opinion cannot be unconditionally accepted 

 we find on the other hand in Gartner's experiments a noteworthy con- 

 firmation of the supposition regarding variability of cultivated plants 

 which has already been expressed. 



Among the trial species there were cultivated plants, such Sbfi Aqnilcgia 

 atropurpurea and canadensis, Dianthus caryophyllus, chinensis, and 

 japonicus, Nicotiana riistica and panimlata, and hybrids between these 

 species lost none of their stability after four or five generations. 



