THE VARIABILITY IN CULTIVATION OF HARDY FLOWERING PLANTS. 229 



in a fit climate generally increase in stature and luxuriance, but 

 often deteriorate in flower. 



(2) That colour is as constant in cultivation as in nature, 

 and that the great variations we see are for the most part due to 

 selection and crossing. 



(3) That in some cases plants belonging to different countries, 

 and separated into different species by botanists, combine and 

 continue fertile when grown together in gardens. But in the 

 cases of hybridisation of distinct species, the hybrids generally 

 are either barren and so die out, unless continued by cultivation, 

 or they are fertilised by the pollen of one of the parents, and the 

 offspring are inconstant, and there is a tendency in such cases 

 for the hybrid to revert gradually and be absorbed into the more 

 robust parent. 



(4) There is no evidence that luxuriance in cultivation tends 

 to cause sterility ; but where we find an entirely barren garden 

 flower which seems to be a good species, the sterility is due 

 either to accidents of climate or perhaps to the inversion of the 

 species by hybridising, the pollen -parent having been simply 

 reproduced in an improved form by the seed-parent. 



(5) The causes which produce double flowers are various and 

 ill-defined, but are generally favoured by a warm soil and 

 climate. 



MICHAELMAS DAISIES. 



By Mr. Daniel Dewar. 



[Bead October 4, 1892.] 



Two years ago I was invited by the Council of the Eoyal Horti- 

 cultural Society to act with the sub-committee which had under- 

 taken to examine and correctly name the collection of cultivated 

 Asters (Michaelmas Daisies) brought together at Chiswick, and 

 the outcome — although our labours are by no means finished — 

 is this short paper on the Michaelmas Daisies of our gardens. 

 Coming so soon after the great Conference on Asters and Sun- 

 flowers, which took place at Chiswick last year, I am afraid that 

 very little can be added to what was then said on the subject, 

 until at least our work at the Gardens has come to a definite 



