236 GENERAL REVIEW. 



florists' varieties and very desirable ornamental plants. It has 

 often been thought that the relative size of the pollen-grains 

 determined to some extent the degree of facility with which 

 hybrids in the same genus might be produced ; and Gaertner, in 

 alluding to this subject, remarks that the pollen of D. caryo- 

 phyllus fructifies D. superbus, although the pollen of the latter 

 is much smaller than that of the former ; but he adds that D. 

 barbatus and caryophyllus unite imperfectly, whereas D. bar- 

 bato-sinensis easily hybridises with D. caryophyllus $ , D. sinensis 

 being in this case the intermediate member. 



It was observed before that the difference of the number 

 of seeds is proportionate to the degree of elective affinity. 

 Gsertner avails himself of this as a means of estimating this 

 degree in the several species. It may not be uninteresting to 

 give a table of the affinities of a single species, though we can- 

 not enter upon various questions which arise as to the propriety 

 of this mode of estimation. Taking, therefore, normal impreg- 

 nation as unity, we have 



? Dianthus barbatus <J by its own pollen 

 superbus 

 japonicus . 

 Armeria 

 barbato-Carthusianorum 

 sinensis 

 collinus 

 deltoides 



sinensis latif. Schr. 

 Carthusianorum . 

 prolifer 

 virgineus 

 pulchellus . 

 arenarius . 

 diutinus 



i.oooo 

 0.8111 

 o. 6666 



Q-5333 

 0.3111 

 0.2600 

 0.2333 



O.2222 



0.1354 

 O. 1 1 1 1 

 0.0333 

 O.OIII 



0.0096 

 0.0084 



0.0033 



Lychnis. A showy genus of hardy herbaceous plants or 

 annuals, represented in our gardens by L. dioica fl.-pL, L. chal- 

 cedonica (see ' Bot. Mag./ t. 257) a tall-growing herbaceous 

 perennial, bearing flowers of a vivid " Tom Thumb " scarlet. 

 There are white and rosy flowered varieties of this fine old 

 species, and a double-flowered form has been grown in our 

 gardens since the time of Parkinson (1629), who, in the por- 

 trait which prefixes the first edition of his celebrated ' Para- 

 disus,' is represented bearing this flower in his hand. Lychnis 

 coronata (see * Bot. Mag.,' t. 223) is a very handsome half-hardy 

 species from China and Japan, bearing large flat scarlet flowers, 

 the size and shape of Dianthus Heddewigii. This was intro- 

 duced in 1774; and being now procurable, it might be made 



