yo Heterostylism [ch. 



Sutton under the name '' Primrose Queen." To the casual 

 observer this race differs from an ordinary Primula in the 

 fact that the yellow *' eye," instead of forming a small and 

 well-defined pentagon, is continued as a yellow flush ex- 

 tending far over the limb of the corolla. The anthers of 

 these flowers stand at the lower level and the pollen-grains 

 are small ; but the style instead of projecting into the mouth 

 of the tube stops at the anther-level, being thus practically 

 the same length as in the short-styled type. Such a form 

 of flower was called by Darwin homostyled. 



Crosses were made between this homostyle race with 

 the yellow flush and an ordinary thrum with the pentagonal 

 or small eye. F^ is thrum with the small eye, showing that 

 the yellow flush is recessive. F^ gave the following series : 



9 thrum or short-style with small eye, 



3 ,, ,, with the large eye, 



3 ordinary /m or long-style with small eye, 



I homostyle with the large eye like Primrose Queen. 



The long-styled or pin type, which apparently was not 

 put in, is evidently due to the re-combination of the charac- 

 ters. The two pairs of characters are 



Thrum type (domt). Pin type (rec). 



Small eye (domt). Large eye (rec). 



The homostyle is the form which the pin type assumes 

 when the large eye is developed ; but when in F^ the pin 

 type meets the small eye, the ordinary pin or long-styled 

 form is produced. 



/% gave a simple and confirmatory result ; for of the 

 F^ long-styled plants, some proved pure to the long-styled 

 character, while others threw the recessive homostyle. 



White Flowers in F^ from Red x Cream. 



Exactly comparable with the foregoing case is the 

 paradoxical appearance of w/^//^-flowered individuals in the 

 F^ from the cross of a sap-coloured variety with a variety 

 having cream-coloured flowers. For example, in Sweet 

 Peas or Stocks [Afattkiola) when a red- (lowered type is 

 crossed with a cream, F^ is red, without any cream-colour. 



