list of figures - Terry Sunderland

of overall diversity, when compared to Madagascar, SE Asia and the Neotropics
(Richards, 1973). On the African continent, only fifteen palm genera are known, seven
of which are endemic, representing ca. 72 species (Dransfield, 1988b). When
compared with the astonishingly rich palm flora of Madagascar (170 species in 16
genera, with 165 endemic species (Dransfield and Beentje, 1995)) this lack of
diversity is somewhat surprising. In addition to the paucity of genera and species, the
morphological disjunction between these taxa is great and they are not particularly
closely related (Moore, 1973; Moore & Uhl 1982; Dransfield, 1988b). Even within
closely related taxa such as the endemic rattan genera, the wide differences in floral
arrangement and morphology are somewhat surprising 2 . In this respect, the palm flora
of Africa is considered to be the living relic of a previously much richer palm flora.
Indeed, as Dransfield (1988b) suggests, although the fossil record of palms in Africa
is somewhat sparse, sufficient pollen records 3 indicate a much richer palm flora in the
past (Morley and Richards, 1993).
In particular, there is evidence of a sudden increase in the presence and diversity of
palm pollen in the Lower Senonian and Maastrichtian periods (Dransfield, 1988b;
Maley, 1996), suggesting that palms have had a considerable presence in Africa. The
pollen record also reveals the presence of a number of additional pollen types that are
known to be of extinct Palmae (Herngreen and Chlonova, 1981; Morley and Richards,
1993; Maley, 1996) among which were forms close to the present day genus Nypa.
These extinctions are now known to have taken place within the Oligocene and the
Miocene, and whilst palms declined considerably in Africa during this time, they
persisted in large numbers to the present day in the Neotropics and SE Asia. These
main extinction stages correlate with the main phases of climatic deterioration on a
global level which also affected the other tropical regions, yet is has been postulated
that the arid phases that occurred in Africa were much more severe than they were on
the other continents (Maley, 1996).
2 As these genera share similar vegetative morphology but are distinct in reproductive structure, this
suggests that a complex evolution of the Calamoideae alone has occurred in Africa with much
extinction leaving only these isolated lineages.
3 The pollen of the Palmae are useful indicators of changes in species composition over time, not only
of the family itself, but also for the wider forest habitat (Maley, 1996), especially as they produce large
quantities of fairly resistant pollen (Moore, 1973).
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