Breeding experiments which show that hybridisation and mutation etc. 261 



(Cult. 72), is early like the "outside grand-parents", rubricalyx. On 

 the other hand fgrandi flora x rubricalyx) x (rubricalyx x grandiflora) 

 (Cults. 75, 76, 77) is late in blooming, but earlier than (grandiflora 

 X rubricalyx) x grandiflora, about four-fifths of the plants coming 

 into flower in the beginning of August. These facts are in harmony 

 with the results of other double-reciprocal crosses, as will be explained 

 in the next section. 



Fig. 23. (Rubricalyx x grandiflora) X grandiflora. Foliage p. s. narrow. 



These various differences in time of forming stems and time of 

 flowering are systematically expressed in Table VI. 



J. Double reciprocal crosses. 



In a series of crosses between 0. biennis L. and 0. muricata L., 

 DE Vries (1911) obtained results which may be concisely expressed 

 in the following table (VII), using B for biennis and M for muricata: 



