vUntil the end of the 1990s, unravelling the
history of
vegetative staple crops in Africa had to be pursued by indirect methods, notably
historical linguistics
and the study of somatic variation, as no archaeobotanical material was available.
vEvidence from phytoliths is now available from
Cameroun
(Mbida et al. 2000, 2001)
vThere has been controversy over the Cameroun date (see e.g. Vansina 2004; Mbida
et al. 2005) but
they are very much in line with conclusions drawn by researchers, especially
linguists, since the
1930s using other lines of evidence.