420 Tricotyloiis Races. 



selection of the extreme variants of ordinary fluctuating 

 variability. Even the doctrine of unilateral increase in 

 variability as a result of selection is of no help in this 

 case (see § 2, p. 9), for selection could hardly operate 

 so rapidly as to produce its whole effect in a single gen- 

 eration. The old saying of gardeners that the first con- 

 dition necessary for the production of a novelty is to 

 possess it already, also applies to these purely experi- 

 mental races (Vol. I, p. 185 and elsewhere). If the tri- 

 cotylous race does not already exist it cannot, at present 

 at any rate, be either isolated or bred. 



A high percentage in tricotyls is seldom found in 

 wild species. The highest value I have yet found oc- 

 curred in Linaria vulgaris in the spring of 1894 in a sow- 

 ing of the seed of a hemipeloric plant of the race that 

 I was cultivating at that time (see p. 211). There were 

 59 tricotyls amongst the 425 seedlings, i. e., 14%. Amongst 

 commercial seed the prospect of obtaining intermediate 

 races seems to me to be the greatest, as I have already 

 stated, in those sorts which are cultivated on a large scale 

 in the field or in the garden. It is much smaller in those 

 varieties of flowers which are only grown on a small 

 scale every year. Moreover it seems obvious that cul- 

 tivation on a large scale should favor the origin of new 

 races. 



If the intermediate race, which is being sought for, 

 exists in some sample of seed, we may expect to find 

 mean, bettei or inferior representatives of it. If the 

 former is the case the mean character of the race, that 

 is about 50 to 60% of tricotyly is attained at once, and 

 this occurs in the majority of cases, as might be expected 

 and as the table at the conclusion of this section Avill 

 show (p. 439). Individuals with a higher productive 



