Taxon of the Week: Rhaphidophora

Rhaphidophora decursiva growing in the Sydney Botanical Gardens. Photo by Tony Rodd.

As currently recognised, Rhaphidophora is a large genus of about 100 species of lianes (woody climbers) of the family Araceae found in the tropics of the Old World from Africa to northern Australia. Rhaphidophora forms part of the tribe Monstereae whose most familiar member is probably Monstera deliciosa, the Swiss cheese plant of many a garden, and the flowers and fruit of Rhaphidophora are similar to those of Monstera. Some Rhaphidophora species have pinnate or perforated leaves while others have entire leaves. Most Rhaphidophora species do not seem to currently have a great deal of economic significance except as ornamental plants though a small number have been investigated in recent years for their pharmacological properties. Rhaphidophora pertusa stems are chopped up and mixed with rice gruel before being fed to cattle or buffaloes in India to induce oestrus (Santosh et al., 2006).


Rhaphidophora foraminifera. Photo by Eric in SF.

The genera of the Monstereae such as Rhaphidophora, Monstera and Epipremnum have not had their definitions substantially revised since 1908 and are currently regarded by many authors as problematic. They have been primarily distinguished on the basis of reproductive anatomy (Rhaphidophora, for instance, has numerous ovules, punctate stigmas and minute albuminous seeds) but reproductive characters are often at odds with vegetative characters (Hay, 1993) and a revision of the group is overdue (matters were not helped by the suggestion - since shown to be mistaken - that Rhaphidophora and Epipremnum shared the same type species). A molecular study by Tam et al. (2004) also identified polyphyly of Rhaphidophora, with the majority of Rhaphidophora species forming a single clade but a significant minority forming clades with species of other genera.

REFERENCES

Hay, A. 1993. Rhaphidophora petrieana - a new aroid liane from tropical Queensland; with a synopsis of the Australian Araceae-Monstereae. Telopea 5 (2): 293-300.

Santosh, C. R., N. B. Shridhar, K. Narayana, S. G. Ramachandra & S. Dinesh. 2006. Studies on the luteolytic, oestrogenic and follicle-stimulating hormone like activity of plant Rhaphidophora pertusa (Roxb.). Journal of Ethnopharmacology 107 (3): 365-369.

Tam, S.-M., P. C. Boyce, T. M. Upson, D. Barabé, A. Bruneau, F. Forest & J. S. Parker. 2004. Intergeneric and infrafamilial phylogeny of subfamily Monsteroideae (Araceae) revealed by chloroplast trnL-F sequences. American Journal of Botany 91 (3): 490-498.