HYBRIDS BETWEEN HYBRIDS 



345 



3. Hybrids between Homozygotes and Heterozygotes. 



Species Complex constitution 



Heterozygotes : 



CE. muricata X rigens^Hookeri 



Hookeri. 

 CE, Hookeri X ^Hookeri . curvans 



muricata. 



4. Hybrids between Homozygotes. 

 Heterozygotes : 



CE. deserens X subvelans.''blandina , 



hlandina. 

 CE. deserens X subvelans.''purpurata 



purpurata. 

 CE. hlandina X '•blandina. ''purpurata 



purpurata. 



5. Derivatives of Hybrids. 



CE. lute seen s 



(ex suaveolens X 



biennis) . 

 CE. suaveolens x 



pachycarpa. F^ 

 P. 



6. Mutants (v. infra). 

 CE. rubrinervis 



(ex Lamarckiana) 

 CE. deserens 



(ex rubrinervis) . 

 CE. ochracea 



(ex grandiflora). 



let.flavens . *^flavens 



Configuration 



(6) + 4 (2) 

 (6) + (8) 



(6) +4(0 

 (4) + 5 (^) 

 (4) + 5 (2) 



7(2) 



subvelans . paenevelans 

 subvelans.subvelans . 

 acuens . acuens 



(iii) Diploid Mutations. Further, the hypothesis explains the 

 origin of the diploid mutations. Most of these have changed 

 chromosome configurations as the result of further segmental 

 interchange. Two kinds of interchange are probably most important 

 (D., 1931 d) : first, interchange between chromosomes of opposite 

 complexes and, secondly, interchange between chromosomes of the 

 same complex (Fig. 108). 



As an example of the first we can consider the so-called " half- 

 mutants " oiCE. Lamarckiana. This species is a heterozygote made 

 up of two complexes, velans and gaudens. It has a ring of twelve 

 and one pair at meiosis. Take its composition to be as follows : 



velans {A^^B C^D 



gaudens 



\/ \ 



Bf 



D.E 



E^F GJi K„L M„N {OP 



' \ / \ / \ / \ 



Ffi H^ LM N^4) OP) 



