UNIT-CHARACTERS OF PLANTS 149 



or those which are white. Thus in the sweet pea the wild 

 plant has flowers of a purple bi-color, resulting from the asso- 

 ciation of red and blue pigments in a definite pattern. Red 

 flowers may arise by a suppression of a factor for blue. This 

 change alone produces a red flower with wings lighter than 

 the standard (a red bi-color). Another recessive factorial 

 change does away with the lightness of the wings, producing 

 a flower with both wings and standard full red. A corre- 

 sponding change in pattern in purple (the original color), not 

 attended by suppression of blue, produces purple with both 

 wings and standard of full color. A quantitative change in 

 the color factor (a partial loss of color) produces faintly 

 colored varieties known as picotee, either purple or red. In 

 the flowers of many cultivated plants striping, mottling or 

 spotting with white or red comes in as a unit-character varia- 

 tion, as in petunias, snapdragons, etc. 



TABLE 19 



Unit-Characters of Plants 



1. Colors of Flowers 

 (Example, unit-characters of the sweet pea flower.) 



Dominant Recessive 



(1) Colored. White. 



(2) Colored. Slightly colored (picotee). 



(3) Purple. Red. 



(4) Bi-color. Self. 



3. Colors of Leaves and Stem 



(1) Variegated with yellow. Normal green (dominance imperfect). 



(2) Containing much red. With little red (Oenothera, Coleus, maize). 



4. Colors of Fruits and Seeds 



(Example, maize) 



(1) Yellow endosperm. White endosperm. 



(2) Aleurone black. Aleurone red or uncolored. 



(3) Aleurone red. Aleurone uncolored. 



(4) Endosperm starchy. findosperm sugary. 



(5) Endosperm starchy. Endosperm waxy. 



(6) Seed-coat red. Seed-coat colorless. 



(7) Seed-coat variegated. Seed-coat not variegated. 



