STUniKS ox THE GEXETIOS OF FLOWER-COL' )ri!.S, ETC. 97 



Flower-colours ou uue uiul the same i)l(li^■i(^u.■ll are often luoro or less 

 dilTereut in early and late suimuer, jind ulsi> at di/lerent lioin-s of one d;n-. 

 CViloiii-s ill tlu> nlxjvo Table fvre those rocordoil in -Tiily .•uid generally soon 

 after the o^ieuing of flowei-s. 



Factors. 



Before pixxxjediiig further I will iueutit)n the factors concerned in the 

 colour production of vaiieties used by lue. Of course the action of all these 

 fiactoi« has lieen discovered only after many breeding experiments lla^•e been 

 earned on, but in m}- description I ^\•ill take tlie opposite com-se, because I 

 ■\\ill mention the action of the factors at fii'st, and then go on to the crossing 

 experiments. 



The fiictors produciug the fl jwer-colours of Porhdaca are as follows : — 



1. C, fundamental fixctor for the production of any colour, cc-plant being 

 v;liiie : C alone, either in one or double dose, makes flower cn-ange ; 



2. Gr (gilviis), changes the orange colour produced by C into yelloio ; 



3. B changes the orange colour produced by C into red ; 



4. li which I will call hJucinij factor changes the red colour produced 

 by the co-operation of C and It into magenta. B, without U, even in presence 

 of C, has no blueing action. 



The factors specially concerned in the genotypic constitution of flesh- 

 c-olom-ed and white-Ill rac3s wül not be considered in the present paper. 



All my breeding experiments given below lead us to the conclusion that 

 the varieties used by me may Ije expressed in respect to the colours of petals 

 by the following genetical formulae, if we adopt the presence-and -absence 

 hypothesis : — 



CCggi'vhh 

 CCGG)-rhh 

 CCggimhh 

 CCggRIiBB 

 ccggi'i'hh 

 ccggBEBB 



In describing the cross ex^jerimeuts below the letters gg are omitted in 

 genetical formuls», except in the Ci'oss II. 



