90 



THE FLOWERING PROCESS 



VEGETATIVE 

 STAGE STAGE I STAGE 2 STAGE 3 



STAGE 4 STAGE 5 STAGE 6 



STAGE 7 



STAGE 8 



0.0 0.5 I.Omm 



'■■■'■''■■' 



Figure 5-8 

 Drawings of the developing terminal inflorescence primordium (stamin- 

 ate) of cocklebur, illustrating the system of flowering stages described in 

 Table 5-4. See F. B. Salisbury, 1955, Plant Physiol. 30, 327-334. 



size of the bud. The stages are easy to recognize, and buds can be 

 classified much more rapidly than their size can be measured. Of 

 course it is sometimes difficult to classify a particular bud when it is 

 at a stage midway between two of the defined ones. In such cases 

 the plant is arbitrarily assigned to a higher stage, and the next time 

 such a case arises within the same treatment, the lower stage is 

 assigned so that the errors will tend to cancel out when the average 

 flowering stage^ is determined for a given treatment. Half stages can 

 also be used. Averaging minimizes the errors : if there are 10 plants 

 in a treatment and an error of one stage is made in classifying a bud, 

 there will be an error of 0. 1 stage in the Floral Stage. This is quite 



^ The term Floral Stage as used here is meant to imply the average flowering 

 stage for the replications within a treatment. 



