ON VARIETIES IN PLANTS 309 
a previous chapter. Semi-dwarf, carly-flowering sports have appeared 
even more frequently than those of the Cupid type. They have been 
made the basis of the winter-flowering types of sweet peas. Ordinary 
sweet peas pass into a semi-dormant condition fora time after germination, 
growing very slowly until sideshoots have been developed. The winter- 
flowering sorts, however, promptly send up a central axis which begins 
blossoming as soon as it has attained a height of from two to four feet. 
The Blanche Ferry group of varieties apparently had their inception 
in a mutation of this sort which a woman in northern New York noticed 
among some plants of the Old Painted Lady. She selected them for 
about twenty-five years after which they passed into the hands of a 
seedsman. From this stock a series of early flowering mutations have 
arisen in the order shown below. Black-seeded varieties are indicated 
by (6) and white-seeded ones by (w). 
Old oe Lady (b) 
Bright-flowered sport (b) 
(30 years later) Blanche Ferry (6) 
ee _. 
Extra Early Blanche Ferry (5) Emily Henderson (white, w) 
Earliest of all (b) Mont Blane (early white, w) 
| 
Extreme Early Earliest of all (b) Earliest Sunbeams (primrose, w ) 
Earliest White (6) 
Fig. 125.—New varieties of sweet peas which originated by mutation among the progeny 
of Old Painted Lady. 
Hybridization and Selection in Sweet Peas.—The era of extensive 
hybridization in sweet peas dates from about the year 1880, consequently 
we can say but little of definiteness after that time with respect to the 
origin of new factors in the sweet pea save in a few particularly favorable 
cases. Laxton’s Invincible Carmine was the earliest recorded new variety 
which was produced by crossing, and its parents are reputed to have been 
Invincible Scarlet and Invincible Black. We can easily understand, 
therefore, how it originated, for it is apparently merely an improved form 
of Invincible Scarlet resulting from the inclusion of the factor for intense 
pigmentation of Invincible Black in the factor complex of Invincible Sear- 
let. Similarly by hybridization it has been found possible to establish 
families of varieties such as the Spencer, the hooded, the grandiflora, 
and the winter-flowering sorts. Hybridization has throughout been 
merely a means of fully utilizing germinal differences which have arisen 
by mutation. It is true that in most cases we cannot say Just when the 
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