On the Wood Anatomy of the Tribe “Olmedieae” (Moraceae) and the Position of the Genus Olmedia R. & P.

The structure of the wood of the genera Castilla, Helicostylis, Maquira, Naucleopsis, Olmedia, Perebea and Pseudolmedia, considered to belong in the Olmedieae (cf. Berg 1972) is described. The diversity in anatomical structure between the genera is small, and it is hard to distinguish Maquira, Perebea and Pseudolmedia from each other. Castilla can be recognized by its thin-walled and wide-lumined fibres, Helicostylis by its parenchyma distribution, Naucleopsis (usually) by its more numerous vessels with a smaller diameter. A more marked difference is shown by the monotypic genus Olmedia with apotracheal banded parenchyma instead of the paratracheal aliform to confluent-banded parenchyma of the other genera. Septate fibres, which are characteristic for the other genera – some species of Helicostylis excepted – are nearly completely absent in Olmedia. This structural difference is considered as an argument in favour of the exclusion of Olmedia from the tribe Olmedieae (Berg 1977).