128 



difference amounled lo even 14 millimet. As regards this variation, 

 too, it can be added that the flowers on the same cf-bush gene- 

 rally group themselves more equably about their average size, 

 while, in the case of one and the same 9-bush, single flowers often 

 distinguish themselves in size from the others, thereby displacing 

 the average size of these flowers. This last-named circumstance, 

 too, can also possibly be regarded as a, perhaps weak secondary 

 sexual characteristic. 



In spite of the variation in the size of the flowers on the same 

 bush, the individuals can be divided into different classes of size. 

 I have found that, of the 210 bushes, the highest size-class — with 

 an average size per bush of 28 — 28,9 millimet. — was reached by 

 the cT-individuals, while the highest in the case of the 9"ii^divi- 

 duals was characterized by an average size per bush that amounted 

 to only 26 — 26,9 millimet. Of the rf-bushes, 20 reached the size- 

 class of 21 — 21,9 millimet., and of the Q-bushes, 16 reached the 

 size-class of 20 — 20,9 millimet. This measurement, too, is thus in 

 favour of the ef -sex. 



To this may be added, that the variation in the size oftheflower 

 in respect to the average size of the flower in P. fruticosa 

 is considerably greater than in P. argentea, P. anserina and P. erecta^ 

 with which I also undertook measurements. More definitely, the 

 power of variation in question shown by P. fruticosa is not less 

 than nearly twice as great as in the P. anserina and P. erecta, bolh 

 of which vary very greatly. 



With respect to the shape of the coroUa two chief types can be 

 distinguished : 



1) The pelals broad, with the side-edges covering each other; the 

 corolla hereby given a dish-like form, sometimes flat (the usual type). 



2) The petals narrower, not reaching each other with side-edges; 

 the corolla hereby given the form of a ö-rayed står (not so common 

 as the former type, but by no means rare). 



In both types I have observed the following variations in con- 

 formation: 



1) Common are emarginate, lobed or divided petals. This 

 can give rise to supernumerary petals. 



2) Supernumerary petals can also arise by the petalizing of 

 the stamens. This can give rise to ,,double" flowers. 



