164 Observation of the Origin of Varieties. 



details. Although an explanation of Braun-Schimper's 

 series is still wanting, each of the numbers in it (e. g., 

 13, 21, etc.) may figure as a specific character; that is, 

 it may be the constant mean for a particular species. On 

 the other hand they may constitute stages of variation 

 or characterize races whose nature is still unknown to 

 us. We must therefore limit ourselves to a purely em- 

 pirical description. 



It seems desirable to 

 give a general outline of 

 the significance of my ex- 

 periment before I proceed 

 to describe the details. 



The corn marigold is 

 \ery common in cornfields 

 over the greater part of 

 Europe, as also its German 

 names '' Saativiicherblume' 

 and "gelbe Kornbhune' im- 

 ply. It has thirteen ray 

 florets in the inflorescence 

 and fluctuates around this 

 number according to Que- 

 telet's law. A commercial 

 variety, called Chrysanthe- 

 miirn segetiun grandiflo- 

 rwn, whose origin is not known, is distinguished by the 

 possession of larger and more numerous tongue florets.-^ 

 So far as my experience goes, bought seeds of this vari- 

 ety, give rise to a mixture of this and of ordinary C. 

 scgctiun, no doubt on account of the fact that in the 

 nurseries both are grown close together, for practical 



^ RiJMPLER, Vilmorin's Blumeng'drtnerei, 1896, II, p. 507. 



Fig. 29. Chrysanthemum segetum 

 plenum. An almost completely 

 double inflorescence. See also 

 Plate II. 



