CERTAIN RELATIONSHIPS BETWEEN THE FLOWERS 

 AND FRUITS OF THE LEMON' 



By Howard .SI Reed 

 Professor of Plant Physiology, University of California 



The physiological characteristics of the cultivated lemon make it an 

 interesting object for study, since its period of blossoming and fruiting 

 extends through much of the year. On most lemon trees it is possible to 

 find all stages of development between blossoms and mature fruit through- 

 out the year, though in varying amounts. There are distinct cycles in 

 both the vegetative and fruiting activities of this tree whose limits are 

 recognized by those engaged in its cultivation. One of the objects of the 

 present study was to obtain quantitative records of these cycles and 

 especially of the relations between flowers and fruit. 



The present study attempts to discuss : 



(a) The seasonal distribution of the fruit buds; 



(6) The size and productiveness of the inflorescences ; 



(c) The time required for the growth of fruit and the relation of this 

 time to the season at which the buds appear; 



(d) The numerical ratio of flower buds to mature fruit. 



The material studied consisted of a small group of Lisbon lemon trees 

 located on the Limoneira ranch near Santa Paula, Calif. The trees stand 

 in the midst of a large lemon grove and have received good orchard treat- 

 ment with respect to cultivation, irrigation, and so forth. No especial 

 attention in these particulars was given to the trees during the time 

 observations were being made. All were free from injurious insects and 

 fungous diseases. Each month for one year approximately 50 fruit 

 twigs bearing fruit buds ready to open were selected and marked with 

 identification tags. The twigs were chosen on seven adjacent trees, six 

 of which were full-bearing trees 22 years old. The seventh was 6 years 

 old, but was very fruitful. As soon as a twig was selected an entry was 

 made on a special blank on which full records could be subsequently kept 

 concerning leaves, buds, fruits, and new twigs. Once a month the twigs 

 were examined and the data recorded on special blanks. 



When the first year ended 12 lots of twigs had been selected and marked, 

 and from that time the records on all twigs were continued for another 

 year. Thus the first twigs selected were under observation for two years 

 and the last for one year. A total of 610 twigs was selected and observed, 

 but there was some loss due to the removal of tags by winds, so that the 

 final number was somewhat less than 600. The partial records of twigs 



» Paper No. 54, University of California, Graduate School of Tropical Agriculture and Citrus Experi- 

 ment Station, Riverside, CaUf. 



Journal of Agricultural Research, (153) Vol. XVII, No. 4 



Washington, D. C. july 15. 1919 



" „ Key No. Calif.-20 



100 1 24 — 19 3 



