The Oric/in of Chrysanthemum Seyctinn Plenum. 163 
tained by saving seed from plants such as those figured 
in Fig. 34 A and B, p. 184. 
These remarks also apply to my new Chrysanthemum 
scgctnm plenum. Many specimens set absolutely no seed 
because the doubling has gone too far. For the same 
reason others afford only a meagre harvest. Too drastic 
a selection at the beginning of the flowering period would 
destroy any prospect of a harvest and might even result 
in the extinction of the variety. 
Moreover plants with a high degree of "doubling" 
produce no pollen for the fertilization of the others, 
because they are almost exclusively female ; so that they 
can take no part in the perpetuation of the race in this 
way either. 
My novelty is probably the first horticultural variety 
which has arisen in an experimental culture. By this 
I mean that pure fertilization has been insured since the 
beginning of the culture and that exact and detailed 
records of the course of the experiment have been kept 
every year. Moreover the selection of the seed-parents 
has constantly been carried out from the very beginning, 
with a view to the same ideal. Selection began in 1897, 
the "double" race was obtained in 1900. The selection 
occupied, therefore, a period of three years. 
The corn marigold, being a composite, is admirably 
adapted to form the material for a statistical investi- 
gation of its variability. The number of ray florets 
fluctuate in accordance with the well-known law of LUD- 
WIG based on BRAUN and SCHIMPER'S series. By this 
means the exact composition of a culture can be ex- 
pressed in figures and plotted graphically by recording 
a sufficient number of inflorescences. The course of the 
selective process can in this way be displayed in all its 
