|Fossil Macaranga and Mallotus (Euphorbiaceae): what to believe?
Peter C. van Welzen1, Monica Nucete1 & Han van Konijnenburg-van Cittert1
1Netherlands Centre for Biodiversity Naturalis (section NHN), Leiden University,
P.O. Box 9514, 2300 RA Leiden, The Netherlands
The Euphorbiaceae genera Macaranga and Mallotus are sister groups and found in more or less the same areas: Central Africa, Madagascar and then from India throughout Southeast Asia to China and Japan and via Malesia to Australia and the West Pacific island chains. Many fossils, e.g. wood, leaf fragments, seeds, pollen, and a few flower and fruit parts, are attributed to Macaranga and Mallotus. Quite a number is recorded from areas far away from the present day distribution, e.g., Europe, Alaska, New Zealand, South America and Russia. A critical review of most fossils showed that only very few can reliably be identified as Macaranga or Mallotus. Leaf fragments usually show a general venation pattern, found in many other tropical plant families. Also the wood and seeds of Macaranga and Mallotus are of a general
Euphorbiaceaous type. Only the pollen is typical for the clade that includes Macaranga and Mallotus. Of all fossils only fossils from New Zealand, the Horn of Africa and Japan show enough micromorphological data that they can be identified and for instance be used for dating of a phylogeny.