list of figures - Terry Sunderland

CHAPTER FIVE
HAPAXANTHY AND PLEONANTHY IN AFRICAN RATTANS
5.1 INTRODUCTION
Hapaxanthy, and its alternate state, pleonanthy, are terms that have long been used to
differentiate the flowering behaviour in palms. Despite the fact that hapaxanthy and
pleonanthy have recently been reviewed (Uhl & Dransfield, 1987; Tomlinson, 1990;
Tucker, 1991; Henderson, in prep.) there has persisted some confusion regarding the
inflorescence structure and life form of the rattans of Africa. Recent field observations
have provided further information with regard to the flowering behaviour of the
African rattans and have confirmed the hapaxanthic nature of Laccosperma and the
pleonanthic nature of Eremospatha and the sole representative of Calamus in Africa,
C. deërratus. The genus Oncocalamus, long recorded as being hapaxanthic is now
known to be pleonanthic. Knowledge of the life form of economically-valuable plants
such as rattan is essential if rational decisions are to be made about their long-term
management and sustainable utilisation.
5.2 HAPAXANTHY & PLEONANTHY: A DISCUSSION
A number of palms produce what appears to be a massive “terminal” inflorescence
that, in solitary palms, results in the death of the primary axis. In fact, this structure is
not terminal (Corner, 1966) but is an aggregate of a large number of lateral
inflorescence units borne in the axils of often markedly reduced leaves, which may be
described as antecedent (ibid.). In palms, this condition has been widely termed
hapaxanthy. In essence, there is little morphological difference between hapaxanthy,
and pleonanthy, its alternate condition (Uhl & Dransfield, 1987). In pleonanthy, the
lateral production of inflorescences occurs on the lower portions of the stem which
continues to grow vegetatively and reproduce over a relatively long period throughout
its adult life (Tuley, 1965; Uhl & Dransfield, 1987; Tomlinson 1990; pleonanthic
palms are polycarpic (Dransfield, 1978; Henderson (in prep.)).
The differences between the two flowering states are ultimately physiological (Uhl &
Dransfield, 1987; Baker et al., 1999b). In hapaxanthic palms, the primary axis
undergoes a vegetative phase, which may be up to 50 years in the genus Corypha
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