In regions with abundant rainfall coffee shows a flowering rhythm quite different from that in regions with distinct dry and wet periods. Some species and varieties flower only on the first-year wood, other ones also on the older wood. In some flowering lasts much of the year, other bloom heavily for only a short time. To find whether these differences already appear in the origin of the flowers, descriptions were made of the morphology and development of the branch system, the inflorescence and the flower with Coffea canephora
P. var. robusta
Linden and C. macrochlamys
K. Sch. var. excelsa
A. Chev., and besides of the structure of the inflorescence of C. arabica
L. The structure of the inflorescence of Coffea
L. was shown to derive from the structure of the vegetative parts of the plant. Eight stages could be distinguished in the development of the vegetative points of third degree into flowers.
Between the periodicity of floral initiation on primary side-branches of some Coffea L. spp. and the periodicity of wet and dry periods, different relations were found for different species and varieties, but in the second half of a dry period flowers never arose. Constantly wet regions gave robust plants with few flowers and so smaller yields than regions with periodic drought giving thinner plants with many flowers. Much useful literature on flowering was reviewed.