The Blooming of TniOTHv. 135 



fav()ial)ablc, the ui)i)er third or ])ossiljI\' half of the head blooms 

 first. On succeediiii; da\ s the blooming will extend downwards 

 initil the base is reached. (iMg. 2). If conditions'are e.\ce])ti()n- 

 ally fa\orablc, especiall>" if the ])lant is well ad\aneed in Ijlcxnn- 

 ing, the greater part of the head may come into bloom on the 

 same day. There is, howexer, a narrow zone at the base of the 

 head which the writer has never observed to come into bloom 

 initil the end of the bloomin.q- period for that particular head. 

 Not all of the (low ers in a gi\ en area begin blooming at the same 

 tinic;so that the same part of the head may come into bloom on 

 several successive days. 



The blooming of tiniotlu' is very closelv associated with 

 weather conditions. When these are favorable a large propor- 

 tion of the llcnvers on a gixen head will often come into bloom on 

 the same day while, on the other hand, conditions may be so 

 unfavorable as to entirely prevent blooming. These inlluences 

 seem to be the resultant of several factors so closely interwoven 

 tliat they are diflicult of exact analysis. An attempt was made 

 in 1910 to determine these factors by means of a self recording 

 hvgronieter and thermometer w^hich gives continuous records 

 for humidity and " temi)crature. The results were somewhat 

 inconsistant and failed to give a complete solution of the ques 

 tion. This was probably due in part to the difificulty of secur- 

 ing an accurate hmnidity record at all times though the presence 

 of other factors may also have been responsible for part of the 

 inconsistencies. 



The records, however, showed unanimously that tempera- 

 tures below 50° i'\ or above 65° F. and relative humidity be- 

 low 75° or above 93° at 2 o'clock .\. .m., were followed by little 

 or no blooming, also that several hours of stationary temper- 

 ture and humidity during the preceding afternoon and evening, 

 which condition often prevails during a stormy or cloudv period, 

 resulted in the entire absence of bloom. 



Cornell University, 

 Ithaca, N. Y. 



