ON VARIETIES IN PLANTS 307 
sitions in their day and were doubtless considerably larger than the 
oldest varieties. The first definite reference to size is found in New 
Large Purple, listed in 1845. As this occurs in the darkest color group 
and 15 years before the hybrid origin of a new variety, Blue Edged, was 
even suggested, it probably represents a factor mutation. That such 
mutations actually occurred in the sweet pea is proved by the fact that 
Countess Spencer and Gladys Unwin were both decidedly larger than 
Prima Donna from the very first. The same is true as regards number 
of flowers in the cluster. Prima Donna, according to Beal’s description, 
bore two or three, usually three, flowers on a stalk, while Countess 
Spencer has three to four flowers in a cluster. Many of the recent Spencer 
Fie. 122.—On the left, Snapdragon sweet peas. On the right, double sweet pea, White 
Wonder. (From Beal.) 
varieties bear almost uniformly four-flowered clusters. The original 
form and earliest varieties had two flowers in the cluster. The oldest 
varieties definitely known to bear more than two flowers on a stalk are 
Invincible Scarlet (1865) and Crown Princess of Prussia (1868). As 
these antedate the era of hybridization it is probable that the increased 
number arose by mutation. 
Novelty forms have also arisen from time to time. In double sweet 
peas there are two standards instead of one. In some varieties this 
character has been fixed by selection so that most of the flowers come 
double. It gives the effect of increased size (Fig. 122). In the snap- 
dragon type of flower (Fig. 122) the standard is folded around the wings. 
It is recessive to erect standard and gives a simple Mendelian ratio of 3 
erect to 1 snapdragon in F. 
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