4GG MK. F. N. WILLIAMS ON TOE GENUS DIANTIIUS. 



238. D. yeltjtinus, Guss. Inch Sent. Sort. Boccadif. (1825) 

 p. 2, et PI. Par. (1826) p. 166, t. 32 ; Tanfani, in Pari. Fl. 

 Italiana, ix. p. 297 (Tunica velutina) ; Peichb. Ic. Fl. Germ. 

 Ilelv. f. 5010. 



Velutinus. Caules 40 eentim., simplices strict! graciles, 

 supra angulares, infra teretes. Folia plana ; radicalia laneeolato- 

 liuearia recurva, caulina linearia acuta stricta patentia, sursum 

 descrescentia, vagina folii diam. duplo longiore ; phylla iuvolucri 

 epunctulata mucronulata flores occultautia, exteriora dilute 

 ferruginea ovalia, reliqua elliptica. Inflorescentia capitulis 5-8 

 florum inodororum. Eractese 2 phyllis similes. Calyx submem- 

 branaceus, dentibus obovatis. Petala contigua ; lamina obovata, 

 rosea, =^ unguis. Antherae ovales, cserulese. Semina valde 

 tuberculata. 



Geogr. limits. — N. Crimea, 46°. F. Armenia, 47°. 



8. Algeria, 34°. W. N. Portugal, 8°. 



Note.— Of the 238 species here described, plates are cited for 115 species : 

 in addition 240 varieties are described, and of these plates are cited for 62. 

 Where a figure is obviously bad and misleading, I have not thought it worth 

 while to refer to it. I have not always cited what may appear to be the best 

 plate, but, for convenience of reference and to facilitate the comparison of 

 species, have preferred to quote works in which several species are figured, 

 such as the ' Flora Gneca,' Reichenbach's < Ic. Flor. Germ. Helvet.,' and Witt- 

 kom ni's sumptuous * Icones/ 



Hybrids. 



The species of Dia?itJius hybridize easily ; unlike the genus 

 Sile?ie, in which the species hybridize with difficulty. When the 

 pollen of different species reaches the stigma at the same time, 

 and if that which reaches it later has a greater sexual affinity, it 

 can only be potent when the first is not potent or acts injuriously. 

 In Malta and Sibiscus the production of hybrids can no longer be 

 prevented by their own pollen after three hours, and in Dianthus 

 alter five or six hours. When two species, A and B, hybridize, 

 and the one species A exercises a greater difference on the form 

 and properties of the hybrid than the other species B, the 

 hybrid, or its descendants, if fertilized by A, will revert more 

 quickly to the parent-form A than it will to the parent-form B 

 if fertilized by it. Thus, according to Gartner, the progeny of 

 D. pulchello-arenarius is more variable than that of D. arenario- 



