338 Nutrition mid Selection. 



beds long l^efore they exliibit l)iulsJ The lower pods 

 on the main stem and on the principal branches as well 

 as the lower two-thirds of each pod furnish on the 

 average more double than single plants; the upper sec- 

 tions of the pod and the pods of weaker branches yield 

 more single ones. The proportion of double plants in 

 the harvest can be increased to about 60% cither l^y lim- 

 iting the production of seed by means of culture in pots, 

 or by pruning; and in the best nurseries the finer sorts 

 are usually subjected to this treatment. If the seeds 

 are kept through some years the proportion of double 

 seedlings gradually increases, because the mortality is 

 greater amongst seeds that were destined to produce 

 singles. 



It is stated that in the case of the Balsam and many 

 other double flowered varieties the seeds are rounder 

 and fuller and also smoother than those of the corre- 

 sponding single sorts. The ''double" seeds of Petunia 

 are said to germinate later than the single ones, so at 

 least I have been told by nursery men at Erfurt. In the 

 Composites the central seeds of the disc in double vari- 

 eties are said to be more likely to repeat the anomaly 

 than the marginal ones. All these statements should, 

 however, be regarded critically, and many of them are 

 in need of experimental confirmation. - 



Nevertheless the general rule is that the various seeds 

 of a plant may give rise to offspring of widely different 

 degrees of individual vigor, according to the place of 

 their origin on the parent plant, their size and their 



^ This process which is carried out by children is called csimplcr, 

 in France. The matter stands in need of closer investigation, 



^ Peyritsch has collected references to the earlier literature re- 

 lating to this point. Ziir Aetiologie pclorischcr Bliithciibildiiiigcn, 

 Abhandl. k. k. Akad. Wien, 1877, pp. 135-136. 



