OECHID CONFERENCE. 



425 



to the addition of a factor, while a recessive character is due to the 

 subtraction of a factor. A blotched crispum therefore consists in the 

 addition of a factor to the ordinary typical plain crispunv. The question 

 arises, How was this dominant blotched character added tO' the typical 

 plain crispum? In order to illustrate the point we will take in hand 

 the re-making of a blotched crispum by crossing an ordinary white 

 plain crispmn with one of the yellow blotched species that grows with 

 0. crispum in Colombia — say, 0. luteopurpureum', the result will be, 

 of course, the yellow blotched hybrid known as 0. x Wilcheanum, 

 yellow being dominant to white, and blotched to plain. This natural 

 hybrid appeared in importations before it was first raised in gardens. 



Next we will re-cross this yellow blotched hybrid with another 

 white plain crispum. The expected result, as far as these two characters 

 are concerned, will be that in F^^, out of four plants, we shall get on 

 the average one yellow blotched, one yellow plain, one white blotched, 

 and one white plain. Among the white blotched forms will be found 

 blotched crispums. There can be little doubt that is how the blotched 

 crispums originated in a wild state by natural hybridization. 



Other crossings might, of course, give the blotched crispum, but 

 it (Seems more likely that it should originate from this particular cross 

 than any other on account of the natural distribution of these forms, 

 as estimated by their frequency in importations. Further confirmation 

 may be found in the fact that so far all the imported blotched crispums 

 that have been bred from have proved to be heterozygous, or impure 

 to the blotched character, giving plain forms when mated together. 



For instance, the blotched 0. crispum ' Franz Masereel,' 0. crispum 

 'Leonard Perfect,' 0. crispum Lindeni, 0. crispum Victoria-Regina, 

 0. crispum ' Rossendale, ' 0. crispum Mariae, 0. crispum ' Luciana, ' 

 0. crispum Craw shay anum, and 0. crispum. ' Alphonso ' all give a 

 few plain forms when mated with other blotched forms, showing that 

 each has only a single dose of the blotching factor. This indicates that 

 one of their parents was a plain crispum, otherwise some homozygous 

 blotched forms would surely have turned up amongst them. 



The next step for Orchid breeders to take, therefore, is to breed these 

 heterozygous, or impure, blotched forms inter se. On the average, one 

 out of three of the blotched forms produced in this way should be 

 homozygous, or pure, with a double dose of the blotching factor. These 

 when bred from will give all blotched forms, whether mated with other 

 blotched forms or with plain forms. The interesting blotched forms 

 recently raised by Messrs. W. Bull from 0. crispum ' Franz 

 Masereel ' x 0, crispum ' Alphonso ' would provide excellent material 

 for such an experiment. 



It will, of course, be understood that the blotched character in Odon- 

 toglossums is a very variable one, the blotches vary in size, form, and 

 number, while the pattern varies with the species used. It would be 

 an interesting study to work out the several factors that are no doubt 

 concerned in the different kinds of blotching. The plain form of 

 0. crispum is, of course, usually slightly spotted, especially on the lip. 



