ABOVE: Ficus elastica drawn by E.J.H Corner (1978).

In their treatment of Ficus for Flora Malesiana, Berg and Corner (2005) created a new section STILPNOPHYLLUM to include Ficus elastica  (which originated in in the hills of NE India)  with the Australian stranglers in Section Malvanthera based on external similarities in fig and leaf structure.

This interesting theory was effectively demolished by Ronsted et al in the two papers  based on  DNA studies listed below. The similarities between Ficus elastica and Australian stranglers are most likely due due to convergent evolution rather than a close genetic relationship.

Ronsted et al (2005) 60 million years of co-divergence in the fig wasp symbiosis

Ronsted (2008) Phylogeny of Ficus section Malvanthera

Ficus elastica has never been recorded in the wild, east of Wallace’s Line whilst the Australian Malvanthera Ficus have never been found in the wild, west of Wallace’s Line, with one exception.

Maratua and Wallaces Line
No Australian stranglers have ever been found in the wild west of Wallace’s Line with the exception of Ficus glandifera which is established on Pulau Maratua  off the coast of East Kalimantan.

“In treating Ficus of the Malesian region, Berg and Corner (2005) united monotypic section Stilpnophyllum (F. elastica, the rubber fig.) and section Malvanthera as subsections of an expanded section Stilpnophyllum based on similarities between F elastica and the  Malvanthera species in the venation of the lamina, the length of the stipules and cucullate (hood shaped) caducous basal bracts.

However, F. elastica is distinct from the Malvanthera species in  the shape of the ostiole and in having anthers with separate theca and connate stipules. The Indo-Chinese  origin of F. elastica, which is widely cultivated, also has little geographical affinity to the Australian and Melanesian Malvanthera.

A global molecular phylogenetic  study (Ronsted et at., 2005) including F. elastica, 12 species of Conosycea figs and 11 species of Malvanthera figs strongly suggested that F elastica is member of section Conosycea with a derivative morphology.” Ronsted et al (2008).