PHENOLOGICAL PATTERNS AND SOME ASPECTS OF REPRODUCTIVE-BIOLOGY OF BRACHYLAENA-HUILLENSIS-O HOFFM

The phenology and reproductive biology of the dioecious tree Brachylae na huillensis O. Hoffm was investigated in its natural habitat in Keny a. It flowers and fruits twice every year, but flowering is influenced by the occurrence and amount of rainfall. There are more males per un it area than females and males produce more flower heads per panicle. Fruit production is massive, but up to 80% is subject to predispersal predation by insects. Viability of the dispersed sound fruit ranged fr om 25 to 50% in the laboratory, but was not more than 6% on the forest floor. Loss of viability is accelerated by sunlight and, in the soil, through attack by soil organisms. Complete loss of viability of sound seed in the forest occurred within 15 weeks, but seeds stored in the laboratory remained viable for 61 weeks. Reduction of either of the se xes below a certain level may adversely affect the optimum sex ratio n ecessary for sustained regeneration. Management therefore calls for ca refully planned interventions.