Identifizierung einer bisher nicht zugeordneten Pollenform in mittelamerikanischen Honigen (sog 'Cuba-Form'): Aeschynomene americana L (Leguminosae, Papilionoideae)

Abstract - Identification of a previously unassigned pollen type in Central American honeys ('Cuba-form'): Aeschynomene americana L (Leguminosae, Papilionoideae)
In honeys from Central American provenances such as Mexico (Yucatan, Chiapas) or Guatemala, a pollen type ('Cuba-form') occurs as a reliable marker for those regions (fig 1). The species origin for this pollen is unknown to melissopalynologists. Because the 'Cuba-form' amounts to up to 16% of pollen grains in honey, there is an urgent interest to solve this secret. This is very important for the valuation of botanically characterized honey by the criterion of pollen analysis. During palynological work on a collection of Ethiopian pollen grains the 'Cuba-form' was detected. Pollen grains from plant material of Aeschynomene americana and 'Cuba-forms' of authentic Mexican and Cuban honeys were prepared for light- and scanning-electron-microscopical analyses (figs 2 and 3). The following characterizations were made for all three pollen types: shape: inter-semiangular to circular, 3-colporate, P 16 mm (15-17 μm) x E 18.5 μm (17-20 μm); apertures: syncolporate, ora lolongate, colpi with operculum, margo psilate in equatorial area; exine: sexine reticulate, heterobrochate, lumina up to 0.5 μm, muri simplicolumellate; colour: colourless, grey. The clear correspondence in morphology indicates that the 'Cuba-form' is the pollen of A americana. Further species of this plant occur in similar climatic regions such as in South Africa (A elaphroxylon, A nyassana, with little deviations in pollen morphology), Australia and India (A indica). A abyssinica and A americana are both described as good plants for honey flow in Ethiopia, but only A americana is native in tropical and subtropical America. Pollen morphological, geographical and climatical facts confirm the results.