AND OF PRODUCTS OF METABOLISM 285 



and sown through two seasons, and from the seed then 

 obtained 372 plants were grown. Some of these ger- 

 minated early, and so developed under less favourable 

 conditions than the others. As will be seen from the 

 accompanying figures, these early plants had 9 petalled 

 flowers occurring the most frequently, whilst the later 

 ones had 10 petalled flowers; i. e., flowers with twice 

 the original number of petals : 



Number of petals, 5 6 7 8 9 10 11 12 13 14 15 16-31 

 Early plants, 409 532 638 690 764 599 414 212 80 29 18 20 



Late plants, 40 52 126 165 204 215 177 104 35 8 4 



The somewhat unexpected results obtained by Mac- 

 Leod * with Ficaria ranunculoides may also be attrib- 

 uted, at least in some degree, to the effects of nutrition. 

 MacLeod determined the numbers of stamens and of 

 pistils in the flowers borne by a number of plants at the 

 beginning of the flowering season, and again in the 

 flowers borne by the same plants at the end of the sea- 

 son. The early flowers had on an average 26.73 

 stamens and 17.45 pistils, whilst the late ones had only 

 17.86 stamens, and 12.15 pistils. Also the variability 

 in the number of stamens and of pistils was very dif- 

 ferent in the two cases, the coefficients of variation 

 being respectively 14.1 and 22.3 per cent, in the early 

 flowers, and 18.5 and 27.9 per cent, in the late ones. 

 The method adopted by MacLeod for estimating the cor- 

 relation between the numbers of stamens and of pistils 

 is erroneous, so Professor Weldon has recalculated the 

 constants. f He finds that MacLeod's figures indicate 

 the correlation to be much less in the early than in the 



*Botanisch. Jaarboek., xi., 1897. 

 f Biometrika, i. p. 125, 1901. 



