vl. PREFACE 



hybrids it is felt that the plan is not satisfactory. Primary hybrids usually 

 combine the characters of their parents in such a way that they can easily 

 be recognised, and the variations assumed by different individuals from the 

 same seed pod or the same cross are seldom great enough to prevent 

 them from being recognised, and had the matter gone no further 

 most of the difficulties could have been got over with very little trouble. 

 But we now have hybrids of almost every degree of complexity — primary 

 hybrids recrossed with their own parents, or crossed with other species or 

 hybrids; hybrids derived from two species in which the parents are 

 combined in equal and in unequal proportions ; hybrids derived from three 

 species, from four, and one even from five species ; and while some of these 

 complex hybrids vary enormously between themselves they also in some 

 cases resemble others that are known to have been derived from different 

 crosses. In short there are hybrids whose parentage cannot be fixed with 

 any degree of certainty by an analysis of their characters, because of the 

 amount of reversion that has taken place. Then there is that curious 

 complication that certain crosses which from their parentage appear to be 

 distinct, yet on analysis prove identical. To put the case differently, the 

 same hybrid may be obtained in two different ways. For example, 

 Odontoglossum nobile crossed with O. X spectabile would appear to be a 

 distinct hybrid from O. X Rolfeae crossed with O. X armainvillierense, but 

 an analysis of parentage shows that both are composed of half O. nobile, 

 a quarter O. crispum, and a quarter O. Harryanum. The two have been left 

 under their respective names of O. X percultum and O. X Ossultoni, but 

 it is at least a question whether they ought not to have been regarded as 

 forms of one. And this is only a type of a series. Owing to these 

 perplexing facts it becomes a question whether secondary and more 

 complex hybrids may not in the future have to be treated in a different way 

 from primary ones, or at all events have to be classified separately. The 

 species in certain genera are now becoming so completely linked up by 

 chains of hybrids that we may have to treat these complex forms purely as 

 florists' flowers, selecting and naming only such as show distinct improve- 

 ments on their predecessors and ignoring the remainder. Some such 

 selective method seems almost inevitable in the near future. 



With these remarks we commend the work to our readers, in the hope 

 that their friendly criticism and kindly help will lead to its improvement 

 in the event of another edition being called for. 



To Messrs. R. T., G. B. and F. W. Rolfe our thanks are due for help in 

 reading the proof and in some other details. 



R. A. Rolfe, 



C. C. HUKST. 

 September, 1908. 



