MR. F. N. WILLIAMS ON THE GENUS DIANTHUS. 467 



pulchellus, and the hybrid of D. sinensis and D. Caryoplnjllus 

 reverts to the latter form after 3 or 4 generations, if repeatedly 

 fertilized by it, while it requires fertilization for 5 or 6 genera- 

 tions by D. sinensis in order to revert to that form. Again 

 quoting from Gartner : — " Hybrids usually vary less in the 

 species and varieties of Dianthus in the first generation, the less 

 the degree of affinity between their parent- forms ; species-hybrids 

 therefore less than vaiiety-hybrids ; the former are often charac- 

 terized by a gi eater uniformity, the latter by a greater variability. 

 When hybrids are self-fertilized, the variability increases in the 

 second and succeeding generations the more completely it was 

 absent from the first ; and three different varieties arise more 

 certainly the less the affinity between the parent-forms." Hy- 

 bridity in this genus is a study in itself. I have not given any 

 attention to the subject, but simply append a list of hybrids which 

 have received distinct names, just as I find them, some of which 

 of course have in the first place been described as good species. 



X decrescens, Borb. = deltoides + sinensis, var. asper (Seguieri). 

 X Dufftii, Haussk. = Carthusianorum -f deltoides. 



Xfallax, Kern. =a]pinus + deltoides. 

 X Gremblichii, Asch. = sinensis + Caryophyllus. 

 XGidice, Janka = Carthusiam:rum, var. ferrugineus + libur- 

 nicus. 



in 



X HeUivigii, Borb. = Armeria + deltoides. 

 X Jaczonis, Asch. = deltoides -f superbus. 



X Leitgebii, Eeichardt 



X Levieri, Borb.=liburnieus + sylvestris. 



X Lucce, Asch. = Carthusianorum + arenarius. 



X membranaceus, Borb. = colliiius + diutinus. 



X Mihii y Eeichardt = barbatus + monspessulauus. 



X oenipontanus, Kern.=alpinus + superbus. 



Xsaxatilis, Pers.= sinensis, var. a<per (Seguieri) + monspessu- 



lanus. 

 X spurius, Kern. 



Wulf. 



X Vukotinovicii, Borb. = Carthusianorum + caryophylloides, 



Schb. 



X Warionii, Timb.=fimbriatus + monspessulanus. 

 X Wolfii, Vetter=barbatus + superbus. 



